Which is like not sending a response packet to a DoS.
They've still used up the airwaves, fought with existing clients, and spoke over them to request anything. Sure, you're not propagating that situation but without protocol changes there's no way to say "shut up and don't ask again" or isolate such requests from the parts that actual data-transferring clients are using.
Additionally, what you're doing then is ignoring random "who's there" probes, which is going to affect auto-join of all kinds (remember - the clients are dumb and may just be trying to connect to favoured network while connected to an unfavoured one, which they can't because you ignore their probes).
At best this is a minor tweak, that will impact legacy clients (maybe in protocol-breaking ways?) and not actually help all that much (e.g. if you have even 11Mbps clients, the probes are an incredibly TINY fraction of the data that they would transmit just to stay online once connected, and mostly passive - SSIDs are broadcast quite openly and clients pick up, they don't really transmit until you join - this is how the old WEP-cracking tools of old worked, they could determine the SSID and WEP key without broadcasting a single byte of data over the airwaves. It's the "thousands of clients" bit that's the problem, and ignoring a portion of them still doesn't make it any better - they're old so they're likely to re-transmit more often to get an answer!).
This is hype at best. If you are so congested that can't fit in a client scanning for SSIDs it might want to join, then you don't stand a chance of transmitting any kind of useful data to any connected client anyway.
10,000 clients sensing networks at even 11Mbps (i.e. taking up the most chunk of spectrum, while also taking the greatest portion of their allocated data to do so) is literally lost in the noise.
The problem comes not from the responses given, but the sheer "waiting time" for the airwaves to be clear before it's safe to broadcast any kind of request at all, and that's determined by the protocol of the client, not the AP.