In addition to the “better safe than sorry” case, I finally found a link which makes it explicitly clear:
http://www.iatatravelcentre.com/SA-Saudi-Arabia-customs-currency-airport-tax-regulations-details.htm
Prohibited (also for transit passengers): alcoholic beverages,
firearms or other lethal weapons; drugs of narcotic nature (except
medicines for personal use and if holding prescription); pork
products; natural pearls.
Hope this helps others!
On their website it says “SAUDIA does not serve or permit passengers to carry or drink alcoholic beverages on its flights.”
http://www.saudia.com/HOW-CAN-WE-HELP/More-Information/Terms-and-Conditions/SAUDIA-Terms-Conditions-Passenger-Advice-Notices-Liability#11430b3f2a847210VgnVCM1000001f64e80aRCRD
I read that as meaning you may not have alcohol checked in since it amounts to carrying it.
Credit:stackoverflow.com‘