Packet Validity is Relative

Section 1.3 says both "Even if only one whisker is malformed, all whiskers must be ignored." and "Unknown whisker types are are not invalid."

This means that if a packet contains a malformed whisker of a certain type, the packet is simultaneously considered "not invalid" (valid) for all implementations that do not implement that type, and invalid for all implementations that do. That is to say, some implementations will accept and process all whiskers except the one of the unknown type, while other implementations will reject all of the whiskers.

Perhaps the reaction should be relaxed to reject only the malformed whisker? Or in the case of multi-whisker chains, like the Comment whisker, it could reject all whiskers of the malformed type?