Probably glaringly obvious (but in this case also), but you should make sure that the specific message starts with something highly conspicuous like "DAT KEYSER

Probably glaringly obvious (but in this case also), but you should make sure that the specific message starts with something highly conspicuous like "DAT KEYSERVER KEY REVOCATION REQUEST ID#<token>" to avoid social engineering someone with "Hey can you sign this token so I know you're you?".