Sure they can! But it's always interesting being "inspired" by some great idea. Why? Well, first; because it's a great idea, why not making something like that, and of course they are counting on the people who didn't saw that idea already, and on people who doesn't care really.
We are surrounded with great and original designers and agencies, and of course with those who are copying others ideas, as we cannot do much, we can publish that "inspired" ideas on ours blogs and hope that someone will notice that, maybe the clients or maybe even the ad agencies.