one more thing...
I don't understand what you guys mean when you say drop in visits are ok but they have to take their kids? Why must they take their kids? I think it would make me feel uneasy if someone said you can stop by but you have to take your kid when you leave.
I don't mind if parents stop by unannounced for 15 minutes. I don't make them take their kids...I just offer them coffee and continue doing what I was doing. Sometimes they join me, sometimes they watch, mostly they say they wanna quit their job and do daycare LOL