Insect inspection should be done to a home on a regular basis. And ants can move rather quickly, thus the need for prompt action.
Just like you need to inspect your trees on your property. If you have a dead tree on your property and it falls killing someone. You are responsible as the owner. You have an obligation as a homeowner to take care of your property, not the contractors you hire. I did read your blog, but just do not agree with your logic (blaming an A/C guy for ants infiltrating your system). Apparently your last post "Ants" got out of hand and was closed. And I will not turn this thread into a discussion about ants. But an exterminator takes care of living pests, A/C guys take care of cooling/heating the home. Sounds like you figured that one out though on your own. Good luck with your situation