Perhaps something like this could let you check on whether coupon code was used...

[code=csharp]int CouponUsedCount = Factory.CreateRepo(HccApp.CurrentRequestContext).GetUseTimesForStore("{CouponCode}", HccApp.CurrentStore.Id);[/code]

There's certainly custom code that could be put into the viewsets and/or integration pipeline to look for and run logic against coupon codes, but it would all be custom for this use case at this point in time. There's no reason why someone shouldn't do it though. It's a great option to have.