I would never do it to someone that wasn't a part of my immediate family(my kids and DH or my mom, dad, bro and sis) and never would I trick if it was allergy related. We do things to the kids if we know they aren't allergic, just picky. Like when we went to dinner the other night, my kids who "hate" mushrooms loved the soup and thought the mushrooms were noodles. I tricked DH when we were first married. He had never tried Cheesecake. Claimed to hate cheesecake. So I made a chocolate cheesecake. I told him it was chocolate pie and he ate a big piece. I asked him to rate it 1-10 how much he liked so I knew if I should keep the recipe or not. He gave it an 8 and I gleefully told him it was cheesecake. And now it is one of his favorite desserts. Like I said though, I would never do it to someone I didn't know extremely well and never maliciously. My own DD has peanut and nut allergies and my brother has nut allergies so I would never try to pull one over on someone who had allergies.
And as for intolerances being allergies, I've often wondered if some of my dislikes are allergies. There are certain foods(onions comes to mind) that if I eat something with onion or whatever in it, I will get sick. I've never been tested so I just try to avoid those dislikes.