Gluteal hardness in security guards

Peter Freundlich’s how-to study "Assessing Gluteal Hardness in Security Guards," appears in the special Security Issue of the Annals of Improbable Research. It begins:

Here is something that will almost certainly happen to you at some point in your life, if it hasn?t
happened repeatedly already: You will be engaged in what seems to you to be an entirely innocent
and unobjectionable activity when you feel a tap on your shoulder. Turning toward the tap, you
will fi nd yourself facing a Uniformed Private Security Guard (UPSG), who will inevitably say
one of two things — either ?Do you have permission to do that?? or ?You can?t do that here.?
The author of this study has often been an object of intense study by Uniformed Private Security Guards. In response, he has spent much time in turn studying them and their behavior. Here is the fruit of that study. Read it, and you will have a clear understanding of the concept of Gluteal Hardness. …