Footer Credit Links

Hey Guys,
I design a web sites for people and I always put a link similar to 'Web design & development by XYZ' with a link to my site. Now, I know these links have very little value, but would they affect me negatively?
I for example did a web site which has something like 180k pages indexed and GWT is reporting I have 186,658 links incoming from this site. Would this count towards an 'unatural link profile' warning (because I have one)?

// edit:
I'd also like to mention, that until Penguin, I was spamming it a bit, by putting something like:
(a)Web Design(/a), (a)Web Hosting(/a), (a)Web Development(/a), (a)SEO(/a) by (a)Company Name(/a)
(pointing the various anchors of the kw's to the various sections on my site with the company name to the root of my site).

footer link is a big deal. Why do you say it has little impact ? and if you diversify with your own seo it can`t hurt but don`t spam. 2 max

These links are not doing any harm provided the links are related to personal blogs, web development services and designers.

These links are MONEY.

My sales site for my WP plugin has nothing but footer links pointing to it and it is #3 for its search term and it is a pretty competitive term.....

I have an "unnatural link profile" warning from google in GWT - hence why I'm thinking of removing these footer links, I mean, almost 200k links from 2 different sites (each) alone can seem unnatural - no?