There has been a spa at that location for almost a year. It was called Serenity Spa, and was completely legit as far as I could tell. The spa was sold about a month ago, and the name is apparently New Serenity Spa now. The spa had been for sale for at least a month before they found a buyer.
Despite the location, I doubt it's a LE setup. Hell, the ad is tame by Cityx Allentown standards. Yeah, I'd be more careful than usual about what I say or do, but I'd still be curious enough to give it a shot if I'm in Allentown.