From the ethical perspective:
I have read several guest stories where hosts have either canceled or sent alteration requests asking for 2x or 3x the current reservation price when they realize they under-priced the dates. It sucks for them because you are making them pay for your mistake. It also says something about your customer orientation and business ethics, and it’s an extra low blow to the guest if you only researched the local calendar of events because this particular guest booked those dates. Basically, imagine you are the guest and your host does this to you.
From a pure business perspective:
I think you already know the immediate consequences, which are that Airbnb will fine you $100 and block the dates so they can’t be re-booked through Airbnb, and take away your Superhost status for a year. You might get some longer term backlash if that guest has a popular blog and writes about their experience, but it’s not likely. You also might find you can’t get nearly as high a price as you thought. The lowest risk for you would be to create an account on another short-term-rental site and advertise your listing specifically for those dates at the inflated price and not cancel the current guest until you get a confirmed booking from the other site.
[Edit: I personally wouldn’t cancel.]