It is what I mean. Neither you nor your partner should be standing that close to the T when you are receiving serve regardless of who is actually returning the ball. It doesnt do anything except look silly, risk loss of point, and risk injury. If you want to cut off a potential bad return by your partner you dont have to stand on the T. You can stand well on your side of the court and take a step in after the server hits the ball. Most people do that.
The only difference is that (in mixed especially) some people try to "shield" the T with their body hoping that the server wont risk beaning them so their partner can have an easier time returning the serve. This is such a lame tactic because it works most of the time, especially when a man is serving to a man and both women are at net. The guy definitely doesnt want to bean his (girl) partner in the back nor does he want to bean the opposing teams girl with a serve.
I'm a little confused, probably because I introduced the idea of the receiver's partner into the mix. So let's separate them.
If I am returning in mixed . . .
I stand in a normal position (say, a foot outside the baseline) when the guy serves. From there, I adjust. See, you have to remember that a 3.5-4.0 guy does not own all serves to all lcations yet. I just have to figure out what this particular guy has and then return it.
This will usually encouage the guy to do something else. Overhit. Try less reliable locations. Bust out with a kicker he doesn't own.
Often, the guy will use spin. The answer to that is to stand in closer. But if I do that, the guy will body serve me. So what I do is start in my usual position and the move forward during the toss. I mix it up and stay back sometimes, so he has to guess some.
None of this works against guys who can hit all the spots with different spins, but I have only met a couple of guys who could do this. They were bumped up, thank goodness.
If my partner is returning, I stand at the T, and I maintain that this is the best place to stand. If the serve comes up the middle, I move. If my partner's return is not poached, I move up.