First off, this guy doesn't seem like the type of guy to cause a scene. Not under these circumstances anyway: with his family and daughter's friend for his daughter's 16th birthday..? Come on now. Someone telling me to remove my shirt or leave a theme park because of what's on it would probably have me asking a few questions before I complie
Second, well.. most security guards in Orlando (in my experience), are downright a**holes. Whether you're downtown, by UCF, or at the parks, they think they work for the secret service. It's annoying. They take their job waaaay too seriously, and they act as if they had been chosen by divine right to be a security guard when I can go take a class and get certified for the same thing. They like to display their "power" and it's really, really frustrating. That being said, I've met very reasonable and respectable security guards who know that they aren't cops and that their power is limited.
Third, I don't know what cops people are seeing in Orlando, but most if not all cops are wearing the required uniform, and if they're "undercover" or not in uniform, they almost always have a gun and badge on them, along with a bulletproof vest. I have never seen a cop wearing a shirt that says "POLICE" on it and that's it.. nothing else on him.
Regardless, Universal is a theme park that should be providing security and police force in a time of need. So, that being said, if a situation DID arise, and a cop was needed, there should be Universal-employed security or officers on the scene ASAP. There shouldn't be a need for this guy to get called over to help someone out or settle a situation based solely on the fact that his shirt says "police" on it. And if he does get asked, why is that his fault?
Again, to sum this up, I'm not saying this guy was in the right. Wearing a police shirt in a theme park, to me, doesn't seem like the best idea. But, it also doesn't seem like the wrong one. I wear a FDNY shirt (says "FDNY" in all caps) all the time to different places (HHN, for example) but no one runs up to me when there's a fire asking me to put it out.
If this was a posted rule then it's a different story entirely. But I had no knowledge of guests not being allowed to wear shirts like the one in the story, and lets just say Universal isn't known for voicing their rules too well.