This can actually be both fun and educational for all involved.
We have a local boxing club that would come to the dojang. We'd pair up their students with ours, and have them go at it. Once under boxing rules, once under our rules (but never those stupid WT rules).
Since we train and use hands, our students consistently did pretty well with 'pure' boxing. The boxing students struggled when kicks were added, but even without much training they could learn to throw a reasonable roundhouse or front snap kick to the body.
The Y put a stop to it, because of liability concerns.