This is totally insane for project managers to decide on such a decision on prior to distribution, why not before or during the bounty campaign but rather prior to distribution. Do they think this solves dumping, I know of many projects that locked their token and it even dumped more than they expected. Locking is not the antidote for dumping.
Not informing about the blocking period at the very beginning is very unfair, same asn not informing that KYC will be required.
However, the idea itself is not completely insane. Often the project needs a few months to attract the eyes of investors, especially in the situation in which the market is now. So finally it can also be very profitable for bounty hunters.