It's a bit of a silly immature thing to do and one day you might get yourself into a really bad and dangerous situation.
To say your chances of meeting a pyscho are nil is a bit irresponsible and naiive too, no matter how much screening you do.
If someone annoys or irritates me silence is the best way to deal with them and block them. Not just punters but people in general - ex partners, disloyal friends etc.