Someone bumped this an appropriate time as I just had an expense report rejected because my signature was "just" a line.
I pointed out it was a line with a slight curve, and that it's been teh same signature on every document I've signed for this company over the last 21 years.
I was asked to re-submit, so I just added a bump to the front of the line (and re-wrote over the line itself to make it seamless).
Penmanship. f*ck that sh*t.