HelpSome questions about CD keys.

Hi, I have some questions about CD keys.
1. Do stolen CD keys always get banned every ban wave if you are online during? Is there any way to avoid this?

2. How does battleye know if your CD key is stolen?

3. Is buying CD keys a waste of money if you want to play for a good amount of time(atleast a week) without being globally banned?

So far every CD key I have has been banned in a few hours. Thanks for replying.

1. No they dont unless someone else has been on the CD Key on a diffrent IP in the same day

2.Because if 2 People have been on a CD Key of diffrent ips in one day

3.Pretty Much Unless You buy lifetime keys of somebody but if you dont hack your best of buying a new steam key

PS.I Dont know much about this so this may be invaild information but this is what i think im not to sure tho