I know that for some, the amount of text is not near as much as one of my submissions happens to have...  But just in case, I have come up with a couple of methods to mitigate that.  Both are covered here, but this is the short rundown.

First, the obvious solution.  Re-work the text so that there is nothing on the back that might be printed on by the Postal Service.  After mailing out a few samples to some guinea-pigs I know, and upon deliver I discovered that the post office prints this annoying string of information that they actually need to get things to their proper destination!  I mean.. how rude!  I found that the top and bottom inch/25.4mm will have some form of printed barcode/information placed there.  By re-working the back text so that there is enough white space on the top and bottom there should be no issues with your hard worked information being over written by the postal service.

The second solution is to use some form of removable label to cover the game text so that the post office can still print what they need to but your text is protected.  This is shown in this example here.  While this is a simple fix, it adds a small cost to each postcard going out.  While the cost per card is minimal, I don't think that everyone should go out and buy $4 of Avery 5436 removable labels and use two, maybe a handful more, to send out my cards.

Hopefully enough people see this before printing something as back text heavy as my RogueCard game and they can make the needed changes to remove this concern from their game.

Thanks for reading.