Undercutting isn't RMT activity so that's irrelevant. SE will likely look into it if reported in enough detail but that doesn't mean they'll come up with evidence they feel is sufficient proof of botting to take action against the account. Certainly they will do nothing if nothing is reported.

The worst thing you can do to yourself is obsess over getting undercut by a gil. List your item at what you feel is a fair price and then enjoy doing other things. If the item hasn't sold within a couple of days (or sooner if you know the item should have a more rapid turnover on the MB), check to see how many times the item has sold since you listed it and at what price then adjust your pricing based on what has actually sold. But trying to engage in an undercut war with someone who might be doing nothing more than paying just as much attention to the MB as you are isn't going to accomplish anything.