Can I save seats in a busy cafe while waiting in line?
Why are you saving seats if you are in line?
I don't want any bastards to take my seat
Saving seats in a cafe when you are still in the line is inconsiderate of the other people that need to sit down. Wait in line and when you have your food, then find a seat, not before.
I'd better sit down now just so I have somewhere to sit.
Usually people sit after the get their order. If you are patient a moment you will see that seats open up all of the time.