if your amcas application is filled with too many errors and is a cause for concern that you are either incapable of copying and calculating grades or trying to lie about it, you wont get through the verification process. its simply a way to see if your grades that you put in match your transcript. the drawback of this is simply you're goin to have to do it all over again until you get it right. I dont know if its recorded that you failed the verification process, but im sure regardless if it is or not, you put yourself at a big disadvantage by having to go through the process all over again. They will correct minor errors, but not if there are too many.
On another note, I dont understand why they cant accept electronic transcripts from schools in teh same way that they accept committee letters (VirtualEvals apparently is accepted by most allopathic schools, i cant see why they wont accept electronic transcripts seeing its probably more secure and faster then regular snail mail)