[zulln]

> Though in doing so they will be notified that you have done so.

No. Depends on how you look it up, but you could just send an email (from anonymous account if wanted) to the tax agency asking for someones salary. You get an answer back in a few days without them being notified.

[Cederfjard]

Not their salary per se, to be clear. They will tell you how much income someone paid tax on in the previous tax year.