That seems to be the best way of doing it and keeps everyone happy. However I imagine that way would be impossible to monitor amongst the larger companies hence the more stricter line.
My two brothers travel for business. One is allowed to tag on holidays to his business trip whilst the other - a merchant navy captain is allowed to take his wife with him on one trip a year as long as he pays her fare to join the ship and back home at the end of it. She gets a few months cruise including food and lodgings for nowt. He prefers when she stays at home.