An old boss of mine told me to always sigh for ups packages with a bogus name, he always used Carey Grant, That way if there is a problem you can call the company you ordered it from and say you never received it.
One time a guy came through our drive thru (I work at a subshop) and paid with a credit card that had the name of Homer Simpson on it. The guy was asian, so I imagined that it wasn't really his name. Never did find out how that happened.
While I was half-way done reading the second part of the prank, I thought to myself "he should try it out at Best Buy" because anytime I buy something there (at the Best Buy in Reno, NV), even if it's something as small as a CD, they scrutinize my signatures to see if they match up. lol To my surprise he did...but he didnt go through with the transaction. Too bad
Also, I've once been asked to sign my credit card at the counter because I'd left the space previously unsigned. I did, they accepted it, just like the guy doing the prank.
Edit: after spending 2 years working at a sub sandwich shop where I'd have to build sandwiches according to the customers specifications, I can easily relate to employees who dont give a crap about what signatures look like. I know I sure didnt. Most of the time my thoughts were more along the line of "omg, just take your food and leave. and DONT track mud across the floor I just mopped!"