The presence of armed guards can be effective deterrent, especially to those hot-headed thugs that carry firearms illegally. If anything, it actually makes more sense than seeing armed PPD inside the Apple or Urban Outfitter stores in CC.
I wouldn't get too worried about the bouncers being armed. The PPD will know who they are if they are openly-carrying while standing outside, and most likely they got their LTCF from the Spring Garden PPD office, plus at any time the PPD can request their LTCF to make sure it's valid.
Carrying in Philadelphia (openly or concealed) without a valid license is an automatic PUFA charge from the District Attorney's office.
A couple minor technicalities. LTCF is issued and is valid statewide so you will likely have a lot that are issued in Bucks, Montgomery, Chester, and other counties, not just at the Philly Gun Permit Unit on Spring Garden. Regardless, what really matters is that the armed security guards have to be PA 235 certified. Having a LTCF does not allow you to work as an armed security guard and being PA 235 certified does not allow for you to carry outside of work (see http://www.pafoa.org/law/carrying-firearms/act-235
). I don't know the percentage, but I'd venture to guess a large number of them having both.
Also, It's VUFA, violation of UFA (PUFA). The police cannot automatically demand to see your LTCF without RAS (reasonable articulable suspicion) just like they can't demand to see your driver's license just because they see you sitting in your car unless they can reasonably articulate that they suspecting you of violating the law. Technicality aside, PPD will demand at will without RAS if they see/know that you carry and most licensee will comply.