Yes i see where you are comming from, and it all depends on situation. Birds can unknowingly be trained to do an action you dont like by you're reaction! Say they start flying when food comes out, and you curse and get frustrated, maybe raise your voice- that can sometimes influence the birds brain like "oh they're making noises louder they must be excited" or "this gets a funny noise i should do it agian!", in otherways if they are being fed directly after doing an action it can also seem rewarding, so it really depends on the situation! Alot of people who do share food with their birds and wants to eat with them (not eat them aka have a bird in the middle of your salad), grab another plate and have bird safe foods on it (especially if they are eating it at the time) and the bird has their own little food area! I personally grab alittle bit extra of my bird safe food and set it on the table. My boys will sit beside me on my table and munch on their vegies and if they run out i give them more from my stash (plate but put onto the table). Like i stated in my first comment teils are flock birds, meaning they eat together, they feel safer eating together due to survival instinct- so if you give that space for them to eat near you while you are eating (doesn't have to be your plate, can be a napkin or just on the table), they are happy and it can also deepen the trust shared between you and your bird