Update: accidentally opened the patch doing a valsalva, which my doctor said could help with eustachian tube dysfunction 🙃

If you're just hoarding sand to throw later, that's back to bitch behavior, but at least it shows foresight and indicates confidence in your ability to aim well.

However! If you produce your own sand, that's acceptable.

It's a little sick and twisted to surround your opponent with copies of yourself and bet that they won't hit you. Pretty arrogant. To me, throwing sand at someone's eyes reeks of desperation more than it displays resourcefulness.