Mailing an evanrudecard.com Card to someone is absolutely not illegal in any way whatsoever.
Here is a publication from the findlaw website that explains all the details about the legality of mailing feces, human or otherwise, to someone in the mail.
The short answer is NO. The only exception to this is if you repeatedly do this to the same person over and over again in which case you are crossing the line of harassment.
One of the optional extras you can include with your evanrudecards.com card is a box of actual human crap that will smell worse than your worst nightmare.
The human feces is first placed in a dark colored bag so they can't see what it is until they actually open it and the opening to the bag is tightly sealed with tape in such manner that no smells escape the bag until the person opens it, and then it is too late!
Yes. Filling out the address of the recipient is obviously required but a return address is entirely optional and you even have the option to fake the return address to any name/address you wish.
During the order process on the order page you can check the option that allows you to track the card/package so you will know exactly when the recipient recieves your special card/package.
Now stop giving us shit and place and order!! ;)