Now that's interesting.I've planted a couple tomato plants in the corner of my tobacco plot for years.
I should note that I spray my tobacco regularly with acephate, to prevent damage from hornworms, aphids, etc. But, to prevent this systemic insecticide from drifting onto my tomato plants, I always cover the tomato temporarily with a plastic drop sheet. I don't use any other insecticides on my tomato plants, thus, my tomato is totally unprotected.
My experience, insects are much more attracted to the tobacco, and totally ignore the tomato. I've never had any insect problems on the tomato plants, in about 10 years of growing tobacco. For a few years, I planted the tomato about 15 feet separated from the tobacco plants, still no insects on the tomato. This is my experience with 'companion' planting.