Funny thing, though: also on my Norton "don't scan" list is one that I didn't put there: "\system volume information\". I don't know what it is nor how it got there!
It's probably something Norton put there.
Avast does something similar. There's a discussion about it athttp://community.norton.com/t5/Norton-In...can/td-p/456684
where the poster "SendOfJive" tells why it isn't necessary to scan system volume information (3rd post down).
Can I just keep ignoring what Norton is asking me to do and get on with my life?
I would not get rid of MalwareBytes. It's capable of detecting malware that Norton isn't. I'd complain about it to Norton support though. If I had to choose between them, I'd keep MalwareBytes and find a new antivirus.
Should I get rid of that additional line item that I didn't put there?
It's up to you. I wouldn't scan it regularly, though I might scan it once in a while.