I'm sure others will have more/better input than I do, but I'll give 2 cents' worth. I've pretty much packed the diaper bag with Bumkins AIOs for the church nursery. I used to have them do prefolds tri-folded into a Bummi, and that worked okay. I would just show people how to do it and they happily did it. One time a PF was accidentally thrown away and I didn't know till later. But who cares, it was a PF. Also, sometimes they put it in really strangely and M leaked or something, but that wasn't a big deal to me. But it has been easier with the AIOs. I just tell them, "It's just as easy to put on as a disposable," and show them the absorbent side and the waterproof side.
Also, I often send her in there in something else--typically a SugarPeas hemp diaper with microfleece doubler and a Bummi's cover. All they have to do is take it off and put it in a bag, so it doesn't inconvenience them. I do this for two reasons: I only have so many AIOs and I don't want to 'waste' them. Also, the SP w/ microfleece is more absorbent and comfortable than the Bumkins, so it can get her through a longer period without being changed.