Earlier quoted context omitted.
For reference: to be part of a hotels “rewards program” just requires you to create a free account. What privacy concerns are you alleviating by not signing up for the hotels loyalty program? They are going to ask for ID when you get there and many require a credit card hold.
You can read the terms of service and privacy agreement for that "free account" to find out. In general, the Hotel would not be offering a rewards program if it did not benefit them more than it cost. At the very least they are going to use your "free account" to try to get you to use that Hotel (chain) more.
Who do you think is more likely to sell your information to third parties - a hotel brand that has every incentive to keep your information to themselves or an aggregator?
> cost. At the very least they are going to use your "free account" to try to get you to use that Hotel (chain) more.
And a third party aggregator won’t try to get you to use their site more?