Security researchers already know that they're submitting a patch for a security flaw - there is 0 additional overhead.
> My point was that if security patches are flagged as such from the start, it saves attackers lot of time (and money), as they will no longer have to go through (almost) every patch and evaluate whether it could be fixing a security problem.
Not really.
1. They can just check to see who made the commit - if it's a security researcher, it's obviously a vuln patch
2. The commits are obfuscated in hilariously obvious ways if you know what to look for
3. It's not that hard to look at a commit, it's kinda what they're paid for
> while the defenders won't gain much from that,
When the vuln is found a race begins between attacker and defender. The difference is that attackers know they're in a race and defenders find out two weeks later.