One flimsy excuse that I got in the late 2010s was the following....
I was at the gym and asked a woman out. She claimed that she was traumatized by the end of a relationship and wasn't ready to see anyone. She had moved to my city 6 months earlier, so if there was a relationship, it had ended 6 months earlier. About 6-8 weeks after that, I saw her in the grocery store with some guy. I had to see her at my gym for a while afterward. I think she's changed gyms by now because I have not seen her in a long time at that gym.
So incredibly rude!