Hi Bob,
There is no one magic ticket which will solve all your problems, I think you just have to persevere as each implementation seems to have specific issues. We initiated the Business Function in August 2013 and it was only resolved by March 2014 and this required 2 months of direct SAP support. We literally made a complete list of all the Notes and checked to see if we had the problem, After loading each note we then had to regression test all previous problems which had been solved.
Cancelling carts in error was never a problem we encountered. Provided you have the query set up correctly then when you go into "My Requested Products" you should have a column "ACTION" which allows you to delete any SC.
If you do have specific issues and details, I would be happy to assist where I can.
Ant