I have always bought AVs from local florists or HD.
Well, it is easy to check for the presence of the thrips on AVs, well, for the darker colored ones at least.
Take a good look at the center of the flowers. If you see dusty white stuff (pollen) scattered around on the petals near the center where the yellow stamen (the male part of the flowers), keep looking to see if you see any light to slightly dark brown colored little things crawling around at the center of the flowers. They are the larvae of the brown flower thrips.
I was told by other AV growers that you can pick the infested flowers to easily remove the bugs.
I do not like that because I want to enjoy flowers. lol
I mean in the long run, probably alright, but removing the flowers on the plants I just bought and the possible spread onto my orchids are just not worth it for me.
When I move to a bigger place in the future, I would definitely get a room dedicated for AVs.
My favorites are dark blue violets, dark blue with frilly white edge, light blue, and purple.