I have never pressed after folding the block for mailing-do not want creases where they should not be ;-)
As far as the plastic it helps protect the fabric/block from the weather and from the postal machines...I have seen fabrics make their way home without the envies because they were wrapped in plastic and had a label on them
Yes organization is key with this swap but everyone here is also very friendly and helpful so if you find yourself confused or maybe misplaced a fabric-ask :-) We always will help.
HUgs
April