Ofcourse it is!
Nowadays, I notice most of bounties have strick rules, making bounties more organize and I like that Bounty Manager requesting Proof of Authentication to limit scammer .
It's been one of major mistakes of bounty hunter like me not to read rules and requirements of each bounties ending up not getting stakes so it's very important to read and understand each rules to ensure that we're doing the right thing and not wasting our time and effort.
That's normal dude, having rules and policy in every bounty campaign can also give benefits to any participants who will join in the project also for the owner too. It is something like you have a guidelines for you to have profit through bounty. Which we need to abide all of it if we want to get a rewards in the project as well.