score:1
I have similar tricks done several times, and the airlines are not happy about it, but it works perfectly fine.
Be aware though that:
If you check luggage, you might not be able to check it to an intermediate airport only (they might just not offer that - it is only good for exactly this trick)
You lose all further legs on this ticket, without reimburs*m*nt. Yes, that includes your return trip. So you need to buy two round-trip tickets, one for each way, and repeat the trick each time (or take a normal one-way ticket for one of the directions if you can't make it work).
if these are not an issue for you, go ahead.