You have to make a distinction between imperative as a verb form and the speech act request (in German "Aufforderung"). Whereas there are only two genuine imperative forms (for kommen they are 'komm(e)!' and 'kommt!'), you have many more possibilities of making a request.
One of them is the infinitive form. In former times the pupils had to stand up when the teacher entered the class. After greeting, the teacher used to say
as a command. In the same way you may say to an apprentice or to a trainee who wants to go home without cleaning his worksite
Nicht weglaufen und schön hierbleiben, wir sind hier noch nicht fertig.
You can also make a request by means of a past participle. In military commands it is common to say
Stillgestanden! (= "Attention!")
You can also say to the young runaways from the example above
And as said before, there are many other ways to request a person to do something.
For me, the interesting question is whether πάντα ῥεῖ's analysis is in accord with what I said here. I have to admit, that his perspective matches more closely to the intention of the respective advertising agencies, because they are not authorised to command the readers of their advertisements. They can only make suggestions, and that ist what πάντα ῥεῖ said.
So finally I will keep in mind that there are infinitives that look like ersatz imperatives but can as well be understood as suggestions.