Cancer card

I've heard from several people talk about loved ones with cancer excercising the right to use a cancer card.  I kind of like this idea, it allows other people to show their compassion.  Its my understanding the cancer card is something you can use if you aren't feelin well or are being asked to do something that you don't wan to do.  You can pull the cancer card as an excuse to not do something and no one can say or do a thing about it.  Or it can be used to get a special deal.  Sounds like a genious idea to me.  There are countless times that I've felt like due to my illness I should be exempt from normally required activities.   I also believe pulling the cancer card should gain you access or special privileges to things not everyone gets.
  My only experience pulling the cancer card so far is when I was in Arizona last time.   I pulled the cancer card to get a discount on a hotair balloon ride.  Since the ride didn't  happen I need to see if I can pull that off again this next trip.  Just for the record, balloon rides are a couple hundred dollars, so it was well worth the usage.  I was honest and told the woman I had terminal cancer and its been a dream to go on a balloon ride and asked if they had any discounts.  She immediately offered me and my mom the child's price which is about $100 cheaper than the adult price.  This just goes to show that you can't have a cancer card without people that are going to accept the card and have some compassion.