The union my company works with used to use check cards to do that here. Only they were telling people “yes” meant “I would like more information” rather than “Yes, I would like to join [the union that was offering lower wages and worse healthcare than we were getting at the time.]” (fwiw, I was not management back then. The company was paying us better than what they were promising to fight to get us.)
changed a fair amount from back then. Better leaders, fewer mobsters. Highly recommend unionizing. There’s plenty of managers that give a damn; but corporations certainly don’t.