When I played in restaurants, I didn’t notice the harp absorbing any odors. I did play on two harps which stayed for years in restaurants and did pick up a slight coating of grease on the strings from exposure (for many years) to that in the air, even though they weren’t near the kitchen. It wasn’t hard to get rid of, according to the owners.
Fortunately most restaurants don’t permit smoking anymore, so that won’t be a problem. I’ve seen harps that had an orange tinge from years of exposure to nicotine in the air. Same thing happens to the walls and furniture in the smoker’s home.
The most lingering smells on harps I’ve noticed are from perfumes and hair treatments. Oh, you gave me a chuckle, that was the funniest thread, I think, outrageous. (I know who John Doe is, by the way. And Jane.)