[Stefan118]

You could also copy the default guest message and create the same message in a new notice.
Then you select: User is browsing using style
to the style you DO want to show the message.
For instance, you have 3 styles and a mobile style.
Then you create 3 the same default guest messages, and set every notice to an other style.
That way your mobile style is the only style it doesn't show the message.

Not the best way probably, but the most simple solution.