Mandatory signs are typically blue in color. They are used to indicate actions that must be followed, such as wearing personal protective equipment or adhering to specific safety measures. The blue background with white symbols or text conveys a clear and authoritative message about required behaviors.
You don't have to login it is not mandatory.
a mandatory sign - you have to obey it.
because they are mandatory signs
I believe it was a sign in the ant colony in The Once and Future King by T.H. White. Well, the sign said that which is not forbidden is mandatory, if i recall correctly - it's been years.
Mandatory Insurance
It is not mandatory but in most cases it is appropriate for a model to sign a release, especially if you are a photographer and want to protect your images.
Mandatory Insurance -(APEX)
A black circle traffic sign indicates a mandatory action or instruction that must be followed by drivers.
blue
its not mandatory but it is a sign of respect for the life he/she lived
Delete System32.
Usually its the changing of the colour but in some cases it can be different.