Unlocking a phone dangerous?

I'm a little naive when it comes to cell phones, especially unlocking them. I understand the premise, and I have a very old gsm phone that I'm planning to unlock with codes that I found online. The codes are identical on multiple sites, and many people reviewing the sites claim success. Yet I'm worried that by typing in this series of random numbers and symbols, my phone will be reprogrammed to send out information to third parties who are looking for account numbers and such. Is that even something to worry about? Or is unlocking a phone really as simple as every source makes it out to be? Thanks.

Unlocking a phone is not at all dangerous. No one can get your personal info like bank accounts through this way. Especially trusted sites like Unlock-free.com are very good unlock solution for basic mobile models.

can anyone advise how I can unlock a Sony Xperia P it is locked on Three network. I tried several unlocking outlets and I have been told it too early. give it some 2-3 months. can anyone help please? Thanks you