I'm sure I'm not the first person to have thought of this, but I couldn't find an answer on a search (not sure what to search for).

There seem to be situations where it is cheaper to buy:
AAA->BBB->CCC one way
than
AAA->BBB one way
on the same airline.

If one were to hypothetically buy
AAA->BBB->CCC
on a one way ticket, have only carry on luggage, and then just stop at BBB, what negative ramifications for this are there? I'm sure there must be some sort of penalties for doing something this. The only one I could think of would be if you flight got cancelled and they had to reschedule you, it might be hard to insist on going through BBB?

Thanks for your input.