There be ways, and there be ways, but this sort of thing still happens.
During previous years, the hardware store near me that does a bunch of chick sales during the spring months just didn't have chicks the week before Easter. This year, they've had 100-200 chicks come in on the Wednesday of each week, and they have all sold out by Friday. They had them last week, too, but they were all BLACK (Barred Rocks).
They've maintained a 6 chick minimum purchase all along to try to weed out the clueless impulse buyers, too.
Like a lot of rabbit breeders, I make a point of not having bunnies that are of sell-able age at Easter. I will have some that are too young to sell, but old enough to go make (supervised) visits. That way, kids get to see them, touch them, learn a little bit about them, and then they go home, and nobody gets stuck with a living, breathing party favor that will need care for the next several years. Want to talk to me about getting one in a few weeks when they are old enough to re-home? Sure, here's my number.
If you deal in animals, you can't stop the irresponsible from acquiring them, but there are some things you can do to try to avoid adding to the problem.