I think almost everyone has a "people comfort zone", mine is about 3 to 4 feet away from strangers, minimum, and 2 feet with those I know and feel comfortable with.
If someone were to get too close,provoking,making unwanted advances,making me uncomfortable by invading my space,it would make me nervous but if I got up the courage, I just might try saying, "excuse me, but you are invading my people comfort zone, I suggest(or appreciate)you back off, thank you". Or if someone were to sit down alongside of me, and I felt leerie, I'd quickly pick myself up and move on. As some have suggested here, it is also a good idea to say things like that or just NO, loud so those around hear that and bring attention to the situation.
Lots of luck, warm wishes for you and safety.
Take care now,
DE

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