What sign is put on the back of the car to remind others that they are novices?

Don't Kiss Me: Remind others to keep a proper distance and be lively and humorous.

"Old people and new cars, stay away from me": The reason is clear and the requirements are clear and straightforward.

You can also use: "Beginners are on the road, please take care." : self-evident and polite.

In fact, I think it's best to be careful not to publish anything. Sticking something like this will distract others, but I'm afraid I'll "kiss" it before I can see it clearly. ...