Joining United MileagePlus is completely free, you just sign up.

About the same work as filling out a hotel wifi login.

Completely free as in you don't have to give them money.

But you need to give personal information which also has value.

More personal information than you provide them to purchase the ticket to use the free starlink?

Probably, because you are now associating your internet browsing with your personal information. (I don't know if they have the sophistication to actually do this, but it is very possible.)

The people concerned with that hypothetical can use a VPN.

At most they could see domains, ip addresses, timestamps, and http-only sites (are there any left?)

But the person sitting next to you can see everything.

> But the person sitting next to you can see everything.

Privacy filters are a thing.

you're literally an inch away from someone.

they are essentially looking head on at it.

that may work for business class, but not economy.

privacy filters aren't magic.

Regardless one of the conditions surely is giving them permissions to sell this to starlink as and everyone else. So whether the information is the same is probably irrelevant, how they are using it is.

You realize you have to give them the same informaron to even step foot on the plane?

That's why I exclusively pay cash and don't show an ID when I fly /s