What are some potential issues that could blindside me if I were to turn on Setup > Accounting > Shipping > Charge For Shipping? I don't want anything to start happening, I just want to enable custom Shipping methods to be made available in the web store, so the shopper can select between them, and I have to enable Charge For Shipping before the Online checkbox will appear on a Shipping method. I wonder if I can turn on Charge For Shipping just long enough to turn on Display In Website on each shipping method, then turn off Charge For Shipping and the Display in Website option would still be turned on for those Shipping Methods? I tried that, but saving the Shipping Methods now requires the Account (Shipping) field to be populated where it wasn't before, and then saving causes an alert to pop up:

You have changed the account(s) for this item.  Click OK to update the accounts on existing transactions, or Cancel to stay on this page.

I don't know what will happen to our transactions if I click OK and I don't want to mess things up for everyone. Is there a simpler way to make Shipping Methods available in the Web Store to be selected by the shopper during checkout?