Some companies such as Upper Deck and Fleer have signed
affidavits and other legal documents saying that they have observed the
signing of the cards/items. Autopen machines have been used in the past by
other companies. Just because someone gives you a COA - you can't totally
believe them unless it is signed in front of you.
BRBR

Since you didn't mention Topps or Donruss does that mean they don't have
simliar affidavits? Also can you give a specific example of a card signed by an
autopen? How could you ever tell?