I don't know about the rest of the world, but when *I* am signing a document, particularly one that is detailing what medical procedures for which I do or do not grant my assent, I want it to be CRYSTAL CLEAR that I have signed the document. Not only is my handwriting going to be recognizable as characters belonging to the Roman alphabet, but I'm going to take extra care to ensure that the writing is legible.
Judging from the scrawl on many of these consent forms, I am decidedly in the minority. And I don't merely mean "horrendous penmanship that resembles a signature jotted down in great haste". I mean "squiggles that resemble nothing so much as a freehand approximation of a sine wave". It just astonishes me to no end, every time I see it.
Fortunately, there are printed stickers on 99% of the forms, so I don't have to rely on deciphering that which is utterly illegible. And on the ones that haven't got a sticker, normally I can go to the doctor's schedule for the day and figure out whose form I'm looking at.
Mind you, the DOCTORS also often sign in shorthand. But at least the marks they make are relatively consistent from one form to the next. I've learned to recognize a lot of the doctors' personal hieroglyphs, just from seeing them on so many forms.
But as for the patients... let's just say that any time someone's handwriting makes MY penmanship look good, it's quite a feat. ;-)