Yes, one may use an AT&T device on Cricket without getting it unlocked.
are you absolutely %100 sure that if i take an att locked lumia 925 and put a cricket sim card in it, it'll work, because an att chat assistant that i talked to said that an att phone must be unlocked to work on my providor...have you tested this or do u know anyone who has, i need to know for sure before i go out and buy a phone