If cards pushed faced down over the line are not strictly dead , then wouldn't that force late position players to table their cards allowing you to retrieve your own cards if you beat them ?
A potentially dirty move , why can't the action line represent a muck or not ? What is the line really for?
depends on the casino but usually the line is a betting line!
What about tables without a line like in wsop etc?
Dealer should grab the players cards as soon as they relinquish their hand and muck it! IMO!