The obvious question is, how many crosdover voters are trying to play a game and how many actually intend to vote for Trump? This could be an indication of an iminent Trump general election landslide victory...or not. As the race goes on, it will be more clear.
That’s true. Also at question is, do people respond truthfully to those surveys? Probably most do. But if you are trying to be a party-pooper who knows, since dishonesty is already your main point of participation.
Overall I think open primaries are very unfair to the rest of us.