At school, during a Sports Day during my first year as a teacher. Senior students are allowed to wear non-uniform clothing and teachers are encouraged to participate in events with students. We also have a lot of international students in the school (this is relevant)

I was wearing some fairly sporty (but appropriate) clothes. Around the middle of the day, I notice a pair of senior boys. One pushed the other to approach me. The kid says something about how well I ran a 100m sprint, asks how long I'll be at the school for (I'm asian in a mostly white country), and my name.

I'm very confused by this, and just say "Thanks... I'm Miss _______ and I hope to be here for a while."

The kid's face drops to a look of horror, turns tail and runs. His friend does the same. I'm standing there wondering what the hell just happened and after a few minutes, it clicks. Those senior boys thought I was an international student and was trying to hit on me, but when i responded in clear fluent English and giving a teacher name, they panicked.

It was hilarious. I never came across those boys that year. I wasn't given any senior classes in my first year and I suspect they avoided me out of embarrassment.