City A - City B - City C, all one ticket, roughly $220. The layover in city B is only an hour, and City A - City B is a transatlantic flight. The direct flight for the first leg is about $380. There is a direct flight City B - City C a few hours later for $30.
My question: Is it reasonable to book the full route and the single leg later, in case I miss my connection? This is over $100 cheaper. The second flight gives me a guarantee of when I'll reach the end destination, whereas if I just miss the connection, that specific flight might be full and I could have to wait longer. If I don't miss the connection I will not be taking the second flight.
This feels similar to hidden city booking, but I am planning on going all the way through the trip, so most of the concerns there don't apply. The remaining concern is that airlines won't like or won't allow me to book two flights knowing that I will only take one of them (but not knowing which one at this point).