Have them pay for cleaning but don't void warranty.
*NOTE* This was an email I sent to BOL and Tom replied to me that this was (of course) too long to post in the show and thanked me for sending in this perspective. I would have posted this sooner but my parents who I hadn't seen for 2 years (because of the slings and arrows of outrageous fortune) came up for my birthday and I of course preferred to spend my time with them than posting on forums.
Hi, I am a trained PC Technician and have to deal with used computers and I have had to deal with some fairly bad cases of cigarette smoke.
Because of the electric fields and the cooling air pushed through the system large amounts of dust, mold, mildew, bacteria, hair, and if the environment is humid, some moisture making the mold, mildew, and bacteria. The thing is the heat of the computer largely evaporates any trapped moisture when it is running.
Then there is the cigarette smoke. It isn't just tar, but areosoled ash and exhaled particulates. They are drawn into the computer and stick to plastic surfaces, metal surfaces, the dust (and et al) that already is going into the computer, and itself. Unlike the detritus usually found in a computer, these particles trap moister and don't let it go easily. This can cause corrosion, the shorting of components, and the mold and mildew to grow to a much greater extent.
On the low end this just causes faster clogging of fans and heatsinks, which left uncleaned for a short period of time will block cooling airflow allowing parts such as CPUs, Fans, motherboard chipsets, video cards, RAM modules, and most importantly, Power Supplys to have a much shorter lifespan and higher risk of failure. While hardware has some software protections built in, they focus almost entirely on the CPU and Chipset, leaving the other components to fend for themselves.
In the more worst case scenarios, I have seen a computer a little over a year old with its whole motherboard coated in mold and cigarette smoke (both of which I am allergic to) with rusted and leaking capacitors and burnt RAM DIMMs.
I have also seen an large copper CPU heatsink so caked with cigarette smoke and pet hair that an air compressor could not get it all out and I ended up having to wash it out with hot water and pipe cleaners The CPU was actually melted and the thermal paste turned to burnt clay on the bottom of heatsink.
It can also kill your hard drive quickly if your hermetic seal is broken. I have pulled a dead drive out of a computer that wasn't that bad, but the fine moist particulate got into the drive and stuck to the platter, and then it went from there to the read/write head until it couldn't read anymore. I as a side project managed to clean it enough and get some data off it before the drive died permanently
Without cigarette smoke the dust from computer cases is irritating to skin, eyes, nose and sometime ears. it is similar to working with fibreglass insulation. It can quickly lead to sore throats, sinus infections, and in rare cases even ear aches and infections. With cigarette smoke it is similar to working with iching powder or a number of bad mosquito bites. It can lead to eye infections, sinusitis, mild tonsillitis, and mild laryngitis.
Because of this allot of larger PC repair shops are charging a cleaning fee for your PC if it needs it before they will even look at it. Also alot of places are now hiring or appointing someone to clean the PCs first in what I guess you might call Unclean rooms, separate from the repair areas to minimize sick time taken and time wasted while the technician cleans each PC.
A thing to consider is that this stuff makes your computer if infested with allot of dust or cigarette smoke a kind of Typhoid Mary, as it goes along it merry way before problems for it arises, it is kicking a small amount of this stuff back into the air for you to breathe.
This isn't the only big risk that PC technicians face. In many parts of North America they have to deal with venomous spiders like the black widdow and brown recluse spiders, ant supercolonies that are attracted to electronics and heat, and contagions like Hanta Virus and Influenza. I have seen pictures from working technicians of dedicated and mummified rats trapped in server cases and I have seen a quantum fireball hard drive burst into flames right into a friend and fellow technicians face.
These things don't happen often but they do happen and people should take precautions when they are dealing with hundreds of computers from they don't necessarily know where.
I know you guys and gals weren't intentionally trashing techs, and unless the damage is visible I don't think that Apple should void the warranty, especially if it is true it is not spelled out in the warranty. Maybe the warranty doesn't include cleaning, and if so they should just tell the owner they have to have it proffesionally cleaned by an third party that won't violate the warranty first. Still have some consideration for all the techs that have helped you through the years that have to put up with this for you to have the hardware you use work the way it should.
Love the show;
AKA Robert Clark, The currently unemployed PC Technician working on his industry certifications.