Re: [emergency] [OASIS Issue Tracker] (EMERGENCY-33) Remove Ack and Error msgTypes

Although I don't have a copy handy I seem to recall that the IPAWS profile uses Ack and Error.  Although many, although not all, applications use TCP transport that provide a degree of reliability at a lower level, that's not guaranteed or required.  In any event that still doesn't deal with the potential for bad XML or protocol/profile errors.

I'm not aware of anyone having actually confused the Cancel, which comes from an alert source, with the Error, which is in a different section of the CAP alert and originates from an alert recipient.

Error indicates a rejection of a message by a recipient, while Cancel indicates a retraction of a message by an originator.  The two semantics are quite distinct... possibly it needs to be explained better but that's quite a way from a need to remove the option.