I created this to address my anxiety that my car will be washed while in for service. Whether it be my nicely detailed Mustang or my daily driver, I don't want it to go through an automated car wash or to be treated to a sponge and a bucket of gritty water. I try to remember to tell the service advisor that it should not be washed but that's not a perfect solution as it relies on that person recommunicating it.
For a while I was using a paper version that I printed out from the Adams forums. I wanted something more durable. I considered the Detailers Domain version but, the reviewers are right, it needs to be two-sided. So, I set out to create my own. It's two-sided and, as a bonus, has messages appropriate for both a clean and dirty car.
The thing about creating something like this is that you can't just create one. So, they are available in a very limited quantity here. Buy one and keep it in your glove compartment. Heck, buy one for each of your cars.