I do wish on HBO you could check in your bag (permitting it is HBO regulations) free of charge on all flights. I'd much rather take my usual shampoo and soap bottles rather than decanting it into 100ml bottles. Larger bags I'm fine to pay for.
If this were allowed on all flights, I'd check in my little hang luggage 9 times out of 10. Admittedly, I would take a little laptop bag for electronics and essentials, but this can easily go under the seat in front.