What you write is inconsequential, it's that fact that you do that is important. If you can't write (not a big issue today, but has been not too long ago), you can sign with a X.

The signature itself doesn't carry a lot of weight. Signatures given under threat or deceit are void - which is why important stuff needs to be witnessed or notarized.

This. The name doesn't matter. The signing act is all that counts. Before literate times the illiterate would "sign" by simply marking an "X" on the signature line. If you are under duress you may certainly sign your signature as "Under Duress", if the accepting party doesn't harm you right away at least when you show up in court to dispute it your can point out you signed it as such... but you better be ready to prove and show that you legitimately where under duress or the court won't accept your claim.

Related: http://www.zug.com/pranks/credit/

That's awesome! I have also in the past just scribbled the crap out of a receipt much like a 3 year old trying to coloring a solid shape with a pen as my signature a few times. The clerks never care interesting enough. I don't think they even know that the signing act is all that's needed. I suppose when its only for a few bucks they prefer to avoid confrontation. However, according to a merchants credit card agreement, the merchant is responsible for verifying the identity of the person using the card. If they accept unauthorized payment on a card the merchant is liable and takes the loss... never let up or believe a merchant that says you have to pay for fraudulent charges.

Guess the point is deniability: you can claim that you didn't sign it..

of course you'd have to fool handwriting analysis..

Agreed. But if forced to testify in court you would commit perjury if you said you didn't sign it.

If it came out that you intentionally mislead the other person by signing [a false name] [to get out of the obligation], good luck, you're still on the hook and now have opened yourself up to potential criminal and civil fraud charges.

Don't think you can skirt not taking the stand. More than likely this will be in a civil trial and not taking the stand will be viewed by the court and jury that you are hiding something...

If you signed it, that's your mark. It doesn't matter what the mark is. That's why you can sign with an X if you can't write your name.

That would be fraud and you can go to jail for that.