I think it's checkable. You just have to write another program to check the proof, and maybe a meta program that checks that your proof-checking program is corr

I think it's checkable. You just have to write another program to check the proof, and maybe a meta program that checks that your proof-checking program is correct. I think there is a good chance that in the future we have computers coming up with and proving theorems that we don't fully understand (but for which we understand the practical value) and the human contribution will be to write a program that verifies that the proof is indeed correct.