Federal(CBP) clearly prohibited , literally addressed yearly in training. As in 2 year written reprimand -14 days Leave without pay first offense. second is 15 to firing.
you look it up on google, yahoo, ect, nobody cares. you use an official LEO system without a good reason(IE they are standing in front of you, will be in front of you(arriving on flight later in day), ect) it can bite you, all transactions in the system are subject to recorded, individual unique logins so no way anybody is going to be "i didn't look up Obama's passport application to get his birth certificate, musta been someone else...". Some systems are subject to audit a crazy high % of query requests like 5%.
During CLEAR training, the instructor actually had us look ourselves up(WILDLY prohibited by regs, will throw a flag in the IA office from rumor ive heard). Whole class was like "say again, you sure???" . Instructor was aware of this and explained that CLEAR was open source IE NOT government/LEO data and thus wasn't a violation of regs. Chief in front row confirmed. Still was a "uhh what" moment.