Should designer own copyright?

[thumbdesigner]

As designer I do not require link backs. I just put a small comment in the begining of CSS (which can be deleted anytime) like this:

@charset "utf-8";
/* Designed by ThumbDesigner.com */

I am not care of link backs. The sites I do are mainly visited of porn surfers so the traffic is not very good to be send to adult design services website. Well yeah there are webmasters too.. but that's not mean they looking for design services...

I am not care of rights. I am paid to design somebodys project so client owns it! The vaule is not link back but client positive feedback and client reffal to somebody. Thats the best way to say "thank you" to designer who made your project exactly as you want it.