Why are my hotel price checks getting linked?

[Andrews]

I work for a travel newsletter that checks whether booking sites show different hotel prices to new visitors in different regions. Each test is supposed to start clean, so I change the VPN location, use a separate browser profile, and remove all site data before searching. After a few rounds, one booking site starts showing the same verification screen in every profile, including profiles I’ve never used there before. How can it connect those sessions if the IP addresses and cookies are different?

[Kershaw]

A VPN changes where the request comes from, but the browser can still look like the same device. If every test profile exposes an identical browser fingerprint, the booking site can group those searches together without relying on cookies. Run two of the profiles through the same fingerprint checker and compare the results. If they match, the profiles aren’t actually giving you separate test environments. Use isolated profiles with different fingerprints and keep each one paired with the same region during the price check.

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