How often are JWs required to show their DPA / No Blood card anyway??
I remember that people were asked to present one at conventions for super "important" publication releases, but other than that, it's a personal, private document.
If someone was concerned about being found out, you could always have a "fake" wallet in your Meeting™ / Service™ book bag for those special occasions. Or keep it in a locked safe in the event the Elders™ wanted to meet with you and make you prove your loyalty by producing the card.
This is also a good time to remind faders that if you have been hospitalized in the past and declared your JW affiliation, that information will be on your medical records until you make a request to have it removed from your records. This will help you fly under the radar of any JW Elders™ and HLC members who have access to JW patients admitted to the hospital when they show up to make their "Pastoral Visits".