I travel on buses that have CCTV and a big monitor so everyone can see what the 8 or so cameras are recording. People swear loudly (no audio recording but I doubt that is a factor); people prepare cannabis cigarettes; etc etc.

Some people are just anti social[1] and do not care.

[1] preparing a joint isn't anti social! They're not smoking it on the bus. But it is illegal in the UK.