Even if by my recommendation a few real proto are lost, it will be only temporary.
Roms fail, often. This is a suicidal approach, you should treasure what you have, not throw it away just incase. Many of these things are one of a kind, they might NEVER show up again, or have failed since being dumped, especially the older ones. Being protos makes it even worse, they're less likely to be mask parts and so can be accidentally erased if not stored correctly, or just degrade over time. The number of physical Roms MAMEdev seem to be finding which are suffering from bitrot seems to be increasing at a steady rate.
Culling them from the database is a death knell for them because as soon as you do people will just label them as bad and forget them, even if there is a high chance that they're not.
The obsessive fear of loosing what might be legit with a great degree of uncertainty results in keeping junk forever in the database.
BTW I only talk about proto, I don't talk about revisions.
Who cares, it's a couple of bits, a couple of bytes. As I said, better to keep a few uncertain things around than potentially throw away something very important. If it comes to light that they are bad, throw them away THEN and not before, it's not a race.
A proto _IS_ a revision, albeit an early one.
An obsessive need to scrub clean lists of anything uncertain doesn't do any good in the long-run and puts potentially good data at risk. Does that not concern you, not even slightly? That you're causing people to throw away unique, good, interesting revisions just because you want to make your lists 'clean' ?