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You could sign it with a smiley face or a heart!
It doesn't have to be signed. I mail business correspondence from work all the time with out signing it.
Definitely send it good old fashioned 42 cent snail mail. Anything else just makes you look like a lawsuit craving looney toon (or so I was told)
Think of a GW letter just like writing a letter to your Aunt or your Grandma asking for something. Be sweet, if you were wrong say you were wrong and apologize.
But seriously ... I wouldn't draw a heart or a smiley face on the letter lest you might look like a looney toon anyway!