Yes, they say it's better and healthier (at least for adults) to have 5 smaller meals than 3 big ones.
In my pre-baby life I would have 3-4 meals during the day, I would eat when i'm hungry enough, though trying to leave 3-4 hours between the meals otherwise I would end up eating all day long and feeling both full and hungry at the same time.
When you have meals at set times, your body goes into routine and expects a meal at certain time of the day provided that you get up at the same time every day. But I wouldn't push myself into eating at a set time when i'm not yet hungry enough. So, instead of eating half a portion like nappyaddict does (and that's a great thing, by the way! and the whole family can sit at the table together though not everyone will be eating whole portion, just brilliant!), i would wait and eat a full portion later.
But it doesn't work now, as I've been hungry all the time since my DD was born ! Some people say it's because of breastfeeding. And I also tend to eat when DD has a meal.
So, I have lots of snacks in between meals.
But on the other hand, when I can't have a snack (like when we go to drs and spend too much time there or go for a walk and DD doesn't want to go home soon enough, etc) this nagging hunger stops (and it's really more of a desire to nibble at something rather than a real hunger), so i'd prefer to not eat between meals if i could!
It also depends on what you eat (how your body reacts to this food with blood sugar level, whether it's heavy and difficult to digest food, etc) and often thirst is mistaken for hunger.
As for DD, I leave snacks for her around, but she will often eat them only when I pick her up and offer her something, otherwise she just drops a snack when she can go and have something to play with instead.
And overall, i think that eating at set times puts things into routine and order, whereas grazing satisfies immediate needs, so it's difficult for me to compare them, they are just two different things with their own pros and cons.
On one hand, it should be good to show your DCs good eating habits, but on the other hand, they won't remember a thing from their pre-3-year-old-or-so life. I don't want to say "so why bother", i just want to say that maybe it's more appropriate for a bit older age, when they will be able to understand reasons behind good eating habits and will therefore be able to learn something from them rather than have them as a habit they don't understand and appreciate.
Also, i don't know whether grazing is a good thing, as sometimes you will be hungry because you are bored or sad, which is not the best time to eat.
So, i'd go for meals as opposed to grazing but only when DD is hungry as opposed to set times. Also because her sleeping/waking/feeding schedules are too irregular for set time meals. But I will still be offering her snacks when she seems hungry but is not yet likely to be up for a big meal (like when she had a meal just an hour ago and can't be hungry enough for another one)
As for eating after leaving the table. Yes, it doesn't feel right for me to continue feeding DD after she leaves her highchair (i think it's only due to our own eating habits and upbringing) but i still do it as i think it's more important now to satisfy her needs rather than instill any good eating habits because (as i already mentioned) she won't yet understand why she's being forced into a certain way of behaving.