I agree with your general premise, that restricting freedom of movement has not historically been a good thing, but I do also think it's a tragic when a beautiful and interesting place gets absolutely overrun by tourists and as a result gets less beautiful and less interesting, and far less livable for the people who stay there year round and don't leave after a couple days.

I think tourism can be seen as a problem of negative externalities, much the same way as pollution can: for a few businesses in the community, it's a huge net positive. Hotels and restaurants, for example, make big profits off of tourists in popular destinations, but everyone else has to deal with more litter, crowded streets and higher prices, but doesn't see any of the benefit. Just like we regulate pollution, I think it's possible to find ways to regulate tourism to maximize the collective good.

I also think there are ways to regulate tourism without beckoning the "slippery slope" you worry about. For instance, I have been on an island in Thailand which can only be accessed between 8AM and 8PM, does not allow outside plastics of any kind, and charges a modest fee to enter. Measures like that, or increased taxes on accommodation for example, can make it just a little bit harder to visit a popular destination and will probably result in less visitors on average without imposing a quota.