My opnion is people naturally recognize smoke by smell and not site. I have mentioned this to a few other vaping pals and they agreeded. Maybe people just don't pay attention.
I agree on the smell recognition, but I've noticed people do pay attention.
I've vaped in everything from grocery stores, to cafes, restaurants, pubs, clubs and everything in between. People will do a double take if they see you blowing out a smoke like substance from your mouth. I've noticed this with large and small puffs.
But as you've mentioned, there is no smell...and to top it off, the vapor doesn't linger even half the time smoke does, not to mention the lack of a burning stick spilling smoke into the air.
I wonder if they assume they're seeing things