I have done the Kindergarten career day 4 times (I'm a Dental Hygienist) and every time there has always been a SAHM among us, they always have some pretty funny stories to tell. and you are right about the time limit I always bring toothbrushes for them and the big teeth to show them how to brush, but after 20 minutes they are scooting around and you start to lose them. I am sure that by standards they just mean as others have said that it isn't an "adult" business or one that 5 year olds couldn't grasp. There first year that my oldest did it a girl in his class had a dad who was a Dentist and since the teacher felt the kids wqould find that too similiar ( I wish the pay was similiar!)I did the afternoon class instead. I'm sure that's what it is.