I get the OP's side a bit. I have a late fee and I do charge it but I do feel a bit.....degraded maybe? I hate being like "oh ya, don't forget you owe me $10" lol but I would do it because I don't want too send the message that being late is okay. Thankfully the family that has been late 3x has always paid the fee without me asking for it. If they ever didn't though I would just add it on to their next payment email.

I sorta wonder if they think that as long as they pay the fee, that it's ok. They know my fiance works evenings and I don't have children so I think they think "well she's home anyways". I however enjoy my evenings off and I don't want this to continue so I'm considering raising my fee and maybe terminating after 3 late pick ups.