I'm not sure where this trend came from, but I thought I'd give it some clarification.
Moderators do not recognize artist signatures as individual credits, nor do we or will we keep a database of who uses what icon. If you insist on using a signature, these must be supplemented with your pack ID credits.
Don't let all your hard work go to waste.
Plus, having your pack ID on the art lets people know it's you who did it, and will may have people potentially interested in your art.
TL;DR
Pack ID credits are a must!