after thinking about it more, my only reservation is that this seems to be a narrowing of the scope of the tag,
current wiki for tousle:
The act of messing with one's (or another's) hair.
since 'messing with' could mean anything, there's currently many usages of tousle which are very subtle such as post #774989 , post #3606271 , post #725746 , post #1712844
'ruffling' sounds like a more significant action than would apply to these; dictionary examples:
• She affectionately ruffled his hair with her hand as she passed.
• The birds ruffled their feathers (up) in alarm.
so if we go through with this i really think the current usages will need to be sifted manually, moving these subtle hair-touching/fiddling instances to a different more appropriate tag