Wow, Apple. Talk about fail.
Alright, I've worked on a pair of computers in a much worse environment than smokers. They were in a power lawn care equipment sales and repair store (lawn mowers, trimmers, etc). They still operated fine aside from having some malware, but I saw catastrophic failure in the near future for these things if they weren't cleaned out physically soon. I took these computers in the back, grabbed the air compressor hose, hooked up an air jet nozzle, and went to town on these things. They were absolutely filthy. I guarantee they had more crap in them than these smokers' computers. There was probably gasoline and oil residue in them, probably exhaust residue, they were gross. But after an extreme session of air blasting (canned air wouldn't have come close to cleaning these out) and a good wipe down, they were good as new.
If I can do that to nasty old computers sitting in a shop, then you guys can fix computers owned by smokers. There's no excuse for that poor level of service.