I have run into some clients who just refuse. I give them the disclaimer that Sage says it's a no-no and move on. The only issue I have ever seen is where there is a credit card deposit on the order. Because of the Sage Exchange changes, it doesn't seem to like the auth codes and caused errors for me. We had to wipe all the credit card tables, and default cards for AR Customer. Other than that all the open batches came across fine.