Well, goodness, I think this is your second blog in as many days prompted by me.
I think I'm flattered.

The answer is: Whatever works in YOUR family. Plain and simple.
The blog you referenced had one big caveat: the biodad WANTED the cable in the room and the SM did not.
They are clearly, not "on the same page."

If you and your DH work and operate as SD's parents, then that's what you do. (The situation you mentioned, though...I'd let DH bring it up to me. I wouldn't overhear and then question, personally.)

I did all the "mom things" for my SD. We were NCP for years, and then CP for years, and then I was IT. I was the "parent" she lived with, who supported her, who taught her how to drive, etc. I NEVER had the "not my kid, not my problem" attitude with her.

Oh, I hope I count as "veteran." I've been stepping about 20 years.

I would say in the case of an absent BM, there is a huge difference.

However, regardless of what the BM's level of involvement, you simply cannot parent a step-child more than your partner, their biological parent, will allow you to.

Yes, it is an *enormous* double standard; it's also the main reason a lot of SMs end up disengaged. It's heart-wrenching to be told that you're expected to be emotionally available to a child; however, you are not to assist in the teaching, rearing, discipline, guidance, etc. The person who could do this is a person I would, frankly, be frightened of. It's practically an expectation to be a sociopath but only where the step child is concerned. Be outwardly loving, caring, and make the child like you (i.e. exibit charm and charisma), but don't care at all if the child doesn't bathe, over-eats, disrespects you, is being abused/neglected by the other bio, failing classes, refuses to follow house rules, etc.

Anyway, the answer to your question is really in your DH. Does he allow you full parental rights and responsibilities with your SD? If so, by all means, ask, investigate, support, etc. If, however, your DH is of the I'll-tell-you-what-you-want-to-hear-then-do-whatever-I-please-with-*MY*-daughter type, then disengaging could save your sanity.

I would disengage, maybe a little more slowly than some of us here have done. I did it a while back and it works for me. I'd just say 'sorry sweetie, if I am not able to do ALL the mom things then I have to limit myself in other ways too.'
Actually, when I told ours, they said 'you are not our mom so we do not have to do anything you say.' I said 'you are absolutely correct, I am not your mom. Nor do I have to do mom things for iether of you' That worked too!

I don't think that a full time SM can or should disengage with a young skid at home.

I agree it is probably not feasible to disengage when the SKID lives with you full time- I know I couldn't be disengaged under these circumstances. But around particular issues that occur day to day - you may feel you need to pick and choose which ones you want to get involved in, and which to steer clear of. I think that would be my approach - ones I felt particularly strongly about - I would put my oar in - ones I didn't I would leave to DH to sort out.
I actually used to do this when bringing up my adult bio daughters with exH - there was stuff I couldn't or didn't want to handle and I let him do it - as he did with me. He'd get much more involved with their academic stuff, whereas I had had such bad experiences at school (bullying etc) that I preferred not to deal with it. I would be much more involved with personal stuff.

"See, I hate that I'm supposed to be involved with this "poor" lying manipulative SD when it comes to her emotional needs, but I'm supposed to back the fuck off when it comes to discipline and real parental guidance in teaching life skills. It's so conflicting and such a HORRIBLE double standard!"

This is exactly how I feel! I have been expected to intervene when SD is having an emotional crisis or extreme behaviour issue (her BM even asks my advice)but then there are certain things that are apparently none of my business and I have no say in. It just seems wrong.

Frustr8d1, you said as well that your DH seeks out your advice and that you generally feel comfortable asking what's up so you can help out or offer support. I don't see anything wrong with this. Why are you expected to back off and wait for him to come to you to tell you what's going on with SD when you are basically her only mom? I believe that everything that happens with SD is your business because it affects your family, including your own BD, so rather than having the two of them growing up with weird tension about who is involved in what particular situation with each of them, you should let your instincts guide you. I'm sure the choices you make are in everyone's best interest, so why shouldn't you be an equal partner and parent for both of the children in your family? Having said that, it's fine if you want to let DH handle this one on his own and not get involved. It seems like this isn't the first (or last) instance of lying by SD so it's up to you if you think you want to know what's going on or just want to wait and see how it plays out.

If you want to be involved and you are accustomed to that and it works for you and for DH then don't listen to anyone else. I don't think there is a "right answer" but I know that being a SM is a thankless job full of annoying double standards that keep coming up no matter how long you've been at it.

Good luck!