Should I worry that a graduate student somewhere gave a talk using my abstract?

I was looking for mentions of my work on the internet and I came across a seminar series in which a graduate student had given a talk using an abstract of mine. It is unpublished work which I posted on a preprint server. There was no mention in his talk announcement of who did the work, but it was unmistakable because it was in a very specialised area and got a fair bit of media exposure.

On the one hand, I think it is shoddy to give a talk about someone's work without mentioning them in your abstract. The student also never contacted me to ask if he could talk about my work or to get further information etc.

On the other hand, it seems unlikely that the student wanted to pass the work off as his own because, as I said, it already appeared in various newspapers and blogs with my name attached to it.

I thought of contacting the student or his advisor, but it seems a little heavy-handed, I don't know what I should say, and my default behaviour is just to do nothing.

On the other hand, I have been stung before by ruthless people in academia and I feel like I should be protecting my turf, particularly since I am not currently employed by a university.

Best case: it was an innocent misunderstanding, my work got some extra publicity because this student thought it was cool. Worst case: he makes some minor changes and publishes it under his own name and I am once again a doormat.