What you refer to might be a problem however the person copying the clip art would be in trouble also. You have to watch free clip art. Most who use clip art do not read the conditions and license agreement. I personnel do not use clip art that i do not buy... Why spend time cleaning it up when i can buy it ready to go.
Copyright laws are hard to understand, that is why i hired a copyright attorney, to protect my rights. It is a great gray area for most...