If I remember correctly (probably from stories on HN a few years ago), GoDaddy had the ability to "taste" the domains—ie, pay for them, hold them for a few days, then get a full refund if you didn't end up buying through them. I don't recall whether this was something special for large registrars like GoDaddy.
I'm sure tasting still happens on dropped domains, though; registrars have data on search interest and can find dropped domains that are likely to be profitable even taking transaction fees into account.
It's unfair that registrars can abuse their position to pick up valuable dropped domains. But somebody was going to do it in the moment after they drop if not them. That feels like a different and less serious problem.
