Jazzdad, (Jazzmom if your reading)
You can always change implements and store it with the box blade on it. This way, if she wants to mow, tell her if she can change out the blade for the mower, to have fun.
This is unless of course, you really don't like her to take away your seat time... Jazzdad, it is awfully hot out there and I would gladly let her have some seat time. Heck, if she likes it that much, come on over and I'll let her mow some of my pasture (if she can do so safely).
PS, How's the house building coming along?