I have no issues with asking "Did you remember to bring a cheque with you today". I have had parents honestly forget. They go home asap and get me one or their child cannot stay for the day. I have had parents have to go home and come back. They never forget again. I even have a family leave a cheque book at my house, I fill in the amount and leave it out for them to sign, they sign it at drop off and all is good. I have another parent give me 6 months worth of post dated cheques. The problem with that is if something every happens where I have to close then I have to reimburse them.
I don't fool around on payday, I need money at drop off and that is that. My husband goes to the bank at 11am and won't be happy if he has to make 2 trips. I also have a calendar on my bulletin board where the kids hang their coats. I also post all paydays on there.