> I know some actual users get blocked. But the amount of spam we get without it, the amount of bot traffic simply overwhelming the server... It is just too much.
One of the core tenets of system design is Availability. If your service is not available - if your forms are blocking legitimate users - then why are you pretending to have a form submission feature at all? Just to frustrate users?
> One of the core tenets of system design is Availability. If your service is not available
The service won't be available to anybody because of overwhelming unwanted traffic. Now it's available for most potential users. You're speaking econ 101 when everyone else has played out iterated prisoner's dilemmas.