Yep, I’ve dealt with that too and it can be super annoying. I think eBay has instituted a limit on the # of offers you can make on an item to help combat that, but it still happens.
Some lady messaged me Thursday evening asking me if I could get an item to her in WI in time for her husband’s birthday the following week. I told her I would pack it up right away and get it ready to ship out the following morning. She said she couldn’t pay me until the following day (red flag) but I got it ready anyway and of course never heard from her again.
Oh, and some guy messaged me from Norway and asked me if I would help him sell his stuff on eBay because he saw I had some similar items listed. What?