I think it is fine to have the default behaviour not to flash the body; but if people want to explicitly flahs it (I have no idea why, but ok) then we shoudl not stop them. I warning in the manual should do.
so: the first part: if there are not parameters given, to skip the body it fine (yes, it can be a risk, doubles your cookie and doesn't seem to have added value in the  common use case(echo back field inputs))