I don't have any experience with Kopy Kat, however, having been to Panama a few years under 21 its pretty tough to pull anything past them. If you want to avoid the super clubs you may be alright if its a good ID. If you do head out to the two major clubs with a fake go early and with a bunch of cute girls. I found heading in sandwiched between hot chicks usually distracts any door guy I got into La Vela four out of five nights I tried so good luck to you! Also, if you DO get in anywhere -- leave the stamps and wristbands on the best you can. It helps your case greatly. Good luck and party hard!