Check if encoded text exists in footer

Hey out there…

First of all, im not sure if im posting the right place, if not im sorry.

Well i have an issue, a mate told me about a little hack he have seen but non of us can create it or find it.
We have a encoded footer, but wants a script on the theme to do a check and see if the encoded part is still there. and if it has been removed, we want it to print a note on the page that what you just did is not allowed.

Did anyone understand my shit here? lol