I have a nephew here in year 7 who always says 'Hello Jason' when he sees me. I can just do the friendly nod at him and other staff dont know he is refering to me (He cant tell me or my twin apart, who is called Jason).
Apart from the psychic link, being a twin is also good for these situations by not seeming that I'm breaking a school rule letting a pupil use my first name.
I used to work in the bar in a local restaurant and there were quite a few staff who went to the local high school... often after work go to someone's house and have a few drinks or hang out at the local 24-hr McDonalds until the small hours of the morning and stuff like that... being one of the older staff, i usually ended up designated driver and stuff, and frequently dropped my drunken under-age co-workers home..
I then later landed a job at the aforementioned local high school... fortunately all my former co-workers understood that i had to have a certain level of professionalism in the new job, so while at school our relationships consisted of saying hello if we passed in a corridor...
My other half used to coach a junior netball team, so having a couple of her players going to the school was the main source of issues.... hearing the giggle of "thats my netball coach's boyfriend" whenever i'd walk past... one of them pushed the line a bit, making references to my girlfriend and stuff but after explaining the situation to my supervisor action was taken and it quietened down after that...