Homeless people in my area (LA). I don't blame them individually at all, it's a societal issue that some at best got kicked out of their living spaces when rent doubled in the last 5 years. Or at worst were fed fentanyl and had their lives ruined just to line the pockets of some skeevy "medical company" (thank goodness they are having the books thrown at them).

But regardless of fault, they aren't mostly just some people down on luck that at best ask for some change like in my childhood. enough are dangerous, unpredictable, and mentally unwell that public transportation is a non-trivial risk here.

Probably the latter. There doesn't tend to be good enforcement of social norms and etiquette on public transit.

I don't have a local bus or train, what I provided were examples.

> Do you mean it could crash at any moment? Or it is usually full of unsavoury characters?

Both. Buses/trains should be secure places and properly maintained at all times.