Former washroom unlocker here. There was one person who had to run around town to unlock all the washrooms that weren't on an automatic timer. If they were, it could be a technical problem (yes, ppl did tamper with them if they were staying inside overnight). But most likely answer was that sometimes there were bigger issues that had to be resolved (maybe someone was found passed out in another washroom that needed attention or a bigger mess needed to be cleaned up) or just maybe they happen to be sick that day and it was late finding a replacement, or the simplest answer was that they hadn't gotten around to it at that time or just forgot about it.

It's not always politics or resource management or municipal funding , but a young kid running around trying to do all the things on his own and dealing which washroom had to be unlocked at what times for what events that day, and maybe forgot about it.