An ethical question

[Tel]

Now I know that stating what cards you folded during a hand is taboo as it can kill the hand for those left but what about a hand you are in?
Take this scenario, freeroll, ie loose players with everything from beginners to fairly good players. Say 3 limp in and then a 3bb raise which is called by next two. You're next with AA.
You can't just call it and there's a big risk that a 6bb raise (or even more) will get called by half the table. Is it allowed to type in 'AA' and go all-in? This I have tried on a number of occasions with the desired result that most will fold and one or two will call. If everyone folds that is fine too. But is it unethical?
Tel.