Not ok.
My therapist used to have clients drive by her house or sit outside across the street. Made them "feel bette." but my T found it very creepy and unnerving. Sometimes she had to call the police.
I have had the same thing happen. Feeling like youre being watched it very uncomfortable. I have had people park their cars across from my house just to see me come outside.. I have had to get restraining orders on people who "just wanted to be my friends" and would watch me or follow me in a grocery store or whatever. Its not a good feeling.
My advice would be to stop.