I don't see why the meaning should be incorrect: Chambers gives "any absurdity, impropriety or incongruity", and that is surely what we can mean by a "booby" --- Don Mayer is not exactly known to me as a particularly accurate, careful or conventional cluer (in fact he was one reason I gave up doing all the Times Crosswords, as they're so expensive to access abroad). So I would go for SOLECISTICAL, esp. with all those crossers!