Well "hotfim matzot beleilei psahim beshvil ha-tinokkot shelo yishnu " -
"they grab matzot the pesah eve so that the children won't fall asleep".
The simple meaning (pshat) is:
1) that (the adults) eat matza fast
2) They don't give a lot of matza to the children
so they won't eat too much and fall asleep
- but this is usually referred to the taam (explanation)
for this minhag (custom).
Still, (I heard my rav say) there are opinions that this shouldn't
be done. The reasons are:
1) for the fear that they will drop the matza on the earth (thus
making it non-kosher)
2) for the disorder it causes - they say there are more orderly
ways to prevent the children from falling asleep.
Hope it helps,