If you do end up using zip-ties, make sure you use the outdoor-rated black ones. The white ones get degraded by sunlight and nasty stuff in the air, so they get brittle and break. Depending on where you live, it can happen in just a few months.
Yeah, they cost more, and they stand out and your basket won't look as good. Your basket is way more expensive, and it'll look way worse after it flies off the bike and gets run over by a bus.
--Shannon