I experimented with liquid smoke this past month in our more aggressive hive (it is now very docile due to more boxes added). It didn't seem to calm them or send them back into the boxes, in fact I prefer the sugar syrup.
HOWEVER, we noticed a huge amount of black, skinny, icky looking bees and were told we had "black, hairless virus". We have no other signs of illness, mites, etc. Well, today the 2nd hive was a little hyper so we used the liquid smoke. All of a sudden we noticed more of these "sick" bees. We did an experiment with a frame of healthy bees and sprayed them with the liquid smoke and they instantly became "sick" bees. This is after we squished about 20 of the poor things.
Anyone else have any experience like that? No more liquid smoke for us. The weird thing is that the bees kept this appearance long enough for us to take to our local bee supply store (where they were diagnosed). Now we are unsure whether we really have sickness or not. These bees are able to fly and don't hold their wings oddly.
I never liked the liquid smoke. I never used it heavily enough on the bees to see them turn black, but I'm sure the hive smelled like smoke ever after.