If the user only can view the tour, it would not violate terms right? Else this would mean, that every tour send to the client would violate it (and you need to buy a license per client). But if the user could download the tour, and then re-sell it to the client, then it would violate terms ofcourse. With these kind of services it's vague who the user is and who the client.
But what does it mather? Krpano is only 129,- euro (with ipad). You earn that back with 1 client.