One of the factors in the fold is the space for the crankset and pedals to blend. That's why most folders use a high beam that eliminates the interference altogether.
To do that with a diamond or panel frame, you would need to manually rotate the pedal to clear at least, or add folding pedals, and that still might not let you fold it fully flat?
Without it, you might be prone to paint chips and dings at the least, or bent parts at the worst.