Yes, we cover up. I taught in NY, middle school. Workshop model prescribed, word walls, bulletin boards, not more than 20% of premade or teacher-made posters, the rest -students work... No seats in rows! No teacher talking longer than 10 minutes! Teach the whole child, not the subject.. etc, etc, etc. I was shushed by my more experienced and well-meaning fellow teachers from even saying "direct instruction" aloud. So when talking to my principal about what I do, and writing up the course descriptions I used "problem-solving", "case study method", guided discovery" to cover for my very direct teaching. Well, since my results in regents passing were good, the principal seleted to ignore my classroom when walking around the building, but I was warned beforehand about any external visitors so I could move the desks from rows into groups, and do a lab...
Not only does guerilla teaching live, but I'm required to have my lesson plans in a binder on the desk for any passing visitations by admin.
And, due to past experience, I now have a system of code in which my lesson plans look one way (constructivist), but the lesson goes another. Never yet had anyone complain because, I think, they truly don't know what they're looking at.