For you (I'm assuming you're a hobbyist and this is all bonus cash for you), I would do the following:
I don't understand why that should be the case.
At some point the return even on a hobby becomes not worth the effort. Any client can turn out to be a PIA, and paradoxically the less they intend to pay, the more likely they are to be PIAs.
You need to establish first in your own head how much trouble you feel like going through, because you don't know their expectations.
Some of the expectations I set up front for myself is that I don't intend to spend more than 30 minutes per person including processing. I intend to go on location, shoot in one setup, have them select one image each, make a few minor touchups on the spot, burn them a disc, collect the check, and leave. That's the only way they get my lowest rate.
If I have to change setups, that's more money per setup. I'll find someone to honcho on their end: Locate a room, set up the schedule, get people in and out on schedule. I'm not going to do any people herding, or that's more money.
I'll tell them what range of clothing to wear, because if I have to do any more manipulation of lighting than just raising a flag, that's more money.
I'm not going to do any Photoshop magic beyond removing a few blemishes, or that's more money.
But those are all expectations that have to be set beforehand, because even if I had no expenses to pay, there's only so much aggravation I'm going to stand for low pay.