I've put bottles in my case no problems before (wrapped in a plastic bag and padded with clothes around) - though watch out for the luggage x-ray in the USA.

When I last did this it was at SAN and I could hang around, watch them scan my case and then ask them to spin the lock and send it down, so I thought I would...turns out they opened the case examine the bottle. It was no problem, they just said champagne bottles have more lead in them hence couldn't be properly seen on the x-ray and so they checked it manually and were happy.

Since then I've done it at least twice from other places I can recall back in to LON and have had no problems.