Put on your Depends undergarments Glyn
I personally would find it easier to spot a fake autograph than a trimmed card and I have about the same amount of expertise in both cards and autographs.
Someone who knows what they are doing can take a 1 second look at a forged Ruth or Mantle and tell which is real and which is not. Even the good forgeries. Literally 1 second.
Even the best card experts in the world would need black lights, measuring devices and magnification etc. They could spot a fake Wagner in 1 second, but try looking at some T206 PSA 9 that has had 1/132" laser shaved off the top border and tell me how long if ever it takes to spot that!
I am not saying 2 experts would not reach the same conclusion, but a 1 second look with the naked eye is a heck of a lot easier than a few minutes with instruments to determine which is the worthless item.
I realize it is like pissing on a forrest fire to try and convince non autograph guys anything positive about the autograph hobby, but with a ton of experience in both cards and autographs, my "OPINION" is that there are more altered cards in PSA holders than there are fake autographs with PSA/DNA stickers.
No need to start anything on my statement above, it is just an opinion and despite anyone trying to tell me it almost made them piss their pants, I will stand behind it.