l have a very particular sense of grammar. Though l know all of the correct rules, I sometimes bend 'em in ways that seem aesthetically pleasing. (For instance, what you might perceive as many of the upper case 'I's in this are actually lower case 'L's.)
This sign at some typical receptionist's desk already had most of the editing done when l arrived. While waiting, this one capitalization just kinda jutted out at me. Naturally, I altered my environment as to achieve optimal conditions with little effort.
The edit done by me: the slash through the 'P.' This is the standard MLA method of making a capital letter lower case.
Also in Olde English, One might capitalize Words of Importance or perhaps just Nouns.