I wonder how does booking.com pay for the tickets? Do they use a new card for every transaction or do they buy thousands of tickets with the same card? Do they use a corporate card or personal card (which might be against ToS)? If they use a corporate card, isn't it easy for Ryanair to see it and block the transaction?

Also, cannot airline see that requests come from datacenter IPs and not from residential?

It looks like it is super easy to block this on airline side.