Considerate communication for being late

My NPs come home late a LOT. Like twice a week they’re 30+ minutes late. Sometimes it’s work related, sometimes not. Im extremely bothered by this because they give me very late notice or sometimes don’t reach out till after I should be off. They did not disclose this would be the case during interviews (I made it a point to ask) and although our contract has a clause that say I shall be adaptable when emergencies arise, I don’t think staying late for work should be considered an emergency. They take this clause as being able to trap me for hours on end with no advanced communication and then not pay me extra for it (that’s a whole different can of beans).

My question to you: what do you consider a respectable amount of advanced communication if your NPs are going to be anywhere from 30min-2hrs late?

EDIT: I am not asking for nor do I need any advice/input on my current situation. This post is solely because I’m curious what you think is courteous communication when your employer is going to be significantly late.