This is not a good suggestion. I don't care about existing revoke_allowed and I'm not going to waste time removing them. Now instead of a few errors in decisions, I have 648. That doesn't give a good overview and hides real issues.
What suggestion should've been was "ignore whether revoke stuff exists". They are not "invalid nodes" they just don't do anything.
I intentionally and with full awareness suggested for it to be a warning rather than an error (warning as in, non-fatal and silenceable with some application flag or setting). And I hope there's some configurable flags to disable such warnings as desired, but novice modders should certainly be made aware of such things as these, lest we have them wasting time on coding useless ai_will_revoke blocks.
I purposely ignored @ngppgn's suggestion for it to be a warning and made it a full-fledged error.
Unless there is some compelling reason to keep such blocks ("it was there before" I do not consider by itself a compelling reason), it will stay a non-configurable error.
In general the Validator cares about code quality, which is one reason it doesn't accept straNGe_miXEd_casE_teXT. For similar reasons, it does not accept useless code existing simply because it was there before (again, unless there is some compelling reason). Removing the dead code, however annoying it is, is a one-time thing and would not need to be done in the future.