My research and experience with self termite control makes me recollect that tenting is used (and is the only effective way to do it)in certain areas of the country(like maybe Calif, etc.) that have a special type termite that lives in the wood. Tenting is the way to control this type. Around here and in many places we have subterranium termites that live in the soil and they migrate back and forth from the house and the colony in the soil. Soil barrier treatments and baiting is used for control.
Do some research on the net. There is a lot about termites and contact your local county extension agent who has information about your area and your particular type of termite. I read some stuff but didn't pay that much attention since we don't deal with that type of termite and control. Talk to realtors, pest control companies, and others about the tenting process to see if it would affect the value. It may be more common than you think. Around here you typically treat and chase the termites down the street to someone else's house. Treating is common for any house and not a big concern unless there is lots of damage. If the tenting bothers you, don't buy or reduce your price. Chances are any older house may have had termites in the past.