I'm sure there are other tells, like delay between post and reply, or time of day, etc. Epidemiology of bots is just getting started but the tools have to have detectable patterns.

I'm sure that those can quite easily be made to look "human-like."

"Respond within 4-12 hours."

"Do not respond between midnight and 6am EST." (Or CET, whatever makes sense.)

Right now the most obvious traits are the well-known ones that are hard for most LLMs to shake off. Em-dashes, word choices, and the very limited ways in which they structure sentences. Terseness and conciseness is also a tell, which sucks.