If buying used speakers, I’ve made long drives to verify all drivers operate and inspect before loading and transporting myself. If site unseen, there’s risk but stick with places like TMR and you’re pretty safe.
Remember, there’s risk for the seller too. I sold a set of tubes and the buyer wanted money back claiming one of the tubes was bad. I offered full refund for return of all tubes. After several weeks he returned them and I found all tested and worked perfectly. Coincidentally he was selling a tube amp and I suspect he needed my good tubes for demo. There’s risk on both sides.