Drivers can accept the command while they have another client, and after they finish that one they cancel your command, and sometimes you wait 10+ minute for them to finish the other command just to have to search for a different driver because the one that accepted already, cancelled. Some times it can even happen 3-4 times in row. You as a client are penalized if you cancel the command after a drive accepted already, but if the driver make you wait 10 minute and cancel, you cant even report it