Not actually bumped into them, but after qualifying in the Midlands I ended up in a small town, a little south of Birmingham, practicing dentistry. I am originally from West Yorkshire. A local teacher joined the practice as a patient. After recognising his distinctive accent it turned out we had lived less than a mile from each other as children and attended the same school although he would have been 6th form when I was a first year.
In the last 43 yrs since leaving West Yorkshire I haven’t met anyone I was at school with. Even when I have visited the area. To be honest I don’t think I’d recognise anyone now.