> I asked because I'm legitimately curious which parts of the country/world use such draconian contracts.
Since you seem genuinely curious, I'll share some more background on this. The first thing to realize is that not all of your "agreement" with the hotel is necessarily in whatever's presented for you to read or click on at registration. They probably include various "Terms and Conditions" by reference which may not be physically presented to you or even a web click away but they are probably available somewhere on their website or by specific request.
The second factor is that much of the law governing your "contractual relationship" with the hotel is codified not in a contract or even in Ts & Cs but rather in state law and various regulations. Hotels (generally known as the 'hospitality industry') is a fairly highly regulated industry and since the idea of "Inns" pre-dates even medieval times, there's a fair bit which can be traced back to Ye Olde Common Law. Interestingly, in much of the law, the relationship between a hotel and guest is largely based on ancient landlord/tenant relationships, with certain necessary adaptations.
Within this complexity, various hotels assert slightly differing rights for themselves (whether they are "legal" or not is for a judge to decide (which often never happens)) and varying degrees of disclosure and, of course, state laws have some variance state to state, although the major points are mostly unified simply for practicality since most hotels and many customers operate across states.
The bottom line is that, whether or not it's been explicitly presented to you in print, on web click, available somewhere on the company's website or simply by vague reference to "other Ts & Cs" at reservation time or registration, it's probably true that most hotels in most states do have a limited right of inspection of their property which they've rented to you (upon reasonable notice, and within reason, etc) either under explicit or implied agreement or under state law, regulatory permit or simply state case law.
Finally, if you want to actively block such an inspection, hotel security is just going to call the cops to deal with you. Those cops aren't going to be lawyers or versed in all these details. They're just going to do what cops do, look at the situation and determine if the hotel is trying to do something that's obviously wildly unreasonable, and if not, since the hotel does actually own the property (and pays a lot of the taxes supporting the Vegas Metro PD), and since hotel security is just workaday joes following 'big company' national policy, and you're just some visitor who wasn't here last week and won't be here next week, they're going to try to get you to be reasonable, and if you don't comply, and the hotel security supervisor is pissed off at you (or his ex-wife that day) and decides to press the issue - they're just going to arrest you on some bullshit "disturbing", "disorderly" or "trespass" charge, (which the junior assistant DA will dismiss without comment after you spend a long night in jail). And it won't matter if you had an explicit agreement with the hotel or if everyone complied with that agreement at every step - because even if you see a judge, the charge won't even be related to that agreement, regulatory remit or state law. Funny fact: you can't even dispute the legality of a law unless you have standing, which usually means being charged under that law. I've actually intentionally tried to get arrested under a specifically unconstitutional city ordinance as part of a plan created by a constitutional lawyer to get in front of a judge and get the bogus ordinance nullified - and the damn cops figured it out and would not arrest me under that law - despite blatantly violating the law directly in front of the central police HQ - for hours - and repeatedly reporting myself.
BTW, I'm all for standing up to preserve whatever tattered shreds of our privacy and rights remain but I've also learned it doesn't help anything if you pick the wrong hill to die on. And, from just about every angle, this is not a "user winnable" fight to pick. They probably do have some right of reasonable and limited inspection. Your freedom here is the freedom to not stay there. If you are already there and really want to protest the inspection, just ask to see the security supervisor and manager on duty, tell them you're shocked and dismayed and tell them you'd like 15 minutes to privately pack your things and you'll leave (and expect a refund for the current and future days). For grins, you can even go for a full refund of the whole stay and if you're nice about it and come across as a reasonable person who legitimately feels wronged, you might even get it. Because ultimately you're dealing with workaday droids who just want the problem to go away. Low level employees following big company policy are roughly equivalent to vending machines executing firmware, and I try not to expend much energy arguing morals, ethics, law or politics with vending machines, or worse, performing the equivalent of a principled ritual seppuku just to make a point they'll never even comprehend. To make a difference, we gotta be smart and pick our battles wisely.