If I see a Drone I really want I will be relentless and even ask if you would accept extra cash for the info....I don't take cash or pay with cash on eBay, it's Paypal/CC only so there is no question about contact info and phone numbers; those come with the payment method. Those are details we used to ask for from the 1990s, in today's online marketplace, all of that is already embedded and verified in the system (and my policy is no changes allowed). Dozens of transactions and not even once have I spoken a single word to the buyer/seller. When I pay with Paypal, I don't care if they live in Miami or Michigan, I don't care if they are using the parent's address or if their phone number is a mobile phone or a house phone. There are hundreds if not thousands of buyers on eBay so I may have been one of those transactions you mentioned: nobody gets my contact details over Ebay *before* they hit the Pay Now button. That's just asking for trouble giving out your details to anyone for the asking who obviously doesn't really intend to buy; hard pass.
It works more times than not, but yes you need to build up a good buyer reputation also mine is 100% and its not really a good idea to just give out your info. I have had to assure a few sellers for sure but it hasnt really been a problem. I will also say I triple check the seller!