Don't accept lifts from strange men.

Oh yes, I’d have refused if I were the OP, a) because she’d chosen to shop and walk in the rain and b) well, just in case. But I think it highly unlikely that the driver had evil in mind.

I didn’t watch Boat Story though.

I would have refused too, a sad reflection of our times.

What a tricky decision. Probably best to refuse. But I expect it was offered out of kindness assuming you are 50+.
But having watched Boat Story recently I would say I would have refused as well!!

I’d think it was just a kind gesture, in all probability. He saw someone in the rain with their hands (literally) full and thought he would offer to help. It rained heavily here all day and I’d have felt sorry for anyone out in it with heavy shopping.