I don't know whether this is reassuring or worrying, but Haskell has long (always?) pursued this strategy of allowing even more flexible operator names. From http://www.haskell.org/onlinereport/lexemes.html:

> Operator symbols are formed from one or more symbol characters, as defined above …

where 'above' is:

    symbol 	-> 	ascSymbol | uniSymbol<special | _ | : | " | '>
    ascSymbol 	-> 	! | # | $ | % | & | * | + | . | / | < | = | > | ? | @
	| 	\ | ^ | | | - | ~
    uniSymbol 	-> 	any Unicode symbol or punctuation