I think its a good idea to put this in my contract for new clients.

I do have a family who drops off at different times almost every day, between 8 and 9:30. I do find it a bit irritating, as we are out all morning going to the park, trail walks and I don't like waiting around. I also don't like sending texts to inform them where to find us - I stopped doing this. I don't wait around anymore, if they're late they'll have to send me a text and hunt me down. It's not fair to the other children to wait or have their activities delayed. It makes the start to the day much easier when everyone is here by 8:30.