If you break their rules by being armed in their lobby, at what point are they somehow enabled to "take you into custody" at all, whether at gunpoint or not?
I can see them telling you to leave or escorting you off of the property, but custody??
I can't help but laugh at the idea of some "security" noob trying to take the Rhino into custody:
(pimply kid with nasal voice) Um, sir, if you'll please come with me. I'm detaining you."
(The Mighty Rhino) "Unhand me, knave! I say, unhand me or prepare to have thy spleen ventilated!"
(pkwnv) "You can't do that while you're being detained, sir."
(TMR) (whispers) "Kid, you're in over your head. Back off and I won't have to thump you."
(pkwnv) "But sir, it says in the rule book here on page 29, paragr-OOF!"
(TMR) "Betcha didn't think that rule book would fit up there, didja, kid?"
On the positive side, Rhino has as a defense that he was saving the kid some money.
Kid won't have to buy toilet paper for a long time after this.