Is it legal/safe to buy beer and check it in as luggage on a commercial airliner to bring back home?
Yep, only in checked luggage. Wrap it well, they will manhandle the bag. Also account for how heavy it will make the bag.
The only time I think much about this is when coming back from Europe. I declare it on the customs form. Never been stopped or paid duty. The charge is so low, they will spend more on the paperwork than they will collect, so it is not worth their time. Usually they comment on the “good German beer” we are bringing back.
Ahh, I fondly remember the days of bringing 2 cases of beer as carryon. Meanwhile they were stopping little old ladies form bringing eyelash curlers onboard.
I think the airlines don’t care but the revenuers might 
Been there, done that. Actually had my bags checked and the inspector said I was allowed to check the beer. Carry on is not allowed as far as I know.
That was after 9/11/01 before 8/10/07…Liquids were not banned until some pickle washers tried to smuggle
'splosives in their listerine and scope bottles in London. Since then no (edit) carry on liquids in quantities greater than a Eye dropper…
Sucks for me since there are times where I work in both the terminal and concourse. I bring my own sodas to work.
I can even buy a soda on the concourse go to the terminal to work. But I am not allowed to take it back to the concourse…Boooo.
Have had no problem bringing beers with in check luggage. I have been lucky with one or two in a full suit case just wrapped in socks as long as they didn’t clink together. The best method I’ve used when taking beer to friends in Hawaii is to get a shipper box with partitions and heavy cardboard. I’ve had some exterior box damage on occasion but never a broken bottle – yet.