Is redeeming game codes on Steam dangerous? [duplicate]

The redeem system can not really be exploited as far as I know. However, the fact that this individual wanted to have personal information gives a big red flag of the nature of the steam code. There are some scenarios I can think of:

• The key is stolen. The scammer tries to gain your trust this way. I am not a lawyer, but I believe buying or using stolen goods is usually forbidden by law.
• The scammer somehow got malicious code in the steam shop, and gifts you that game/software. They try to get your information that way.
• They are trying to con Steam customer support. They create known knowledge by letting you redeem that key, then they can "tell" customer support the otherwise unknown key to try to proof they are the legitimate owner of the account.
• They want to create a "paper trail" to unsuspecting people to decrease the risk of them getting in trouble and to throw people investigating off.

In either case, it is not worth the trouble. Don't accept the key. Report this particular user for scamming via their profile.

I would not trust that guy at all or redeem his code he is trying to pass off to you. But for the most part as long as you get a steam code from a reputable source (for example, Humble Store, GMG, etc) places like that the codes are perfectly safe. But I would not have any other contact with the person that PMed you. They are clearly trying to scam you.