1) It depends, we'll probably shortly see strong, reasoned arguments for totally opposed opinions. If you're flying someone else's aircraft, do it the way they want you to.
2) Yes, pilots will do checks from memory once they think they are familiar with them (assuming we're talking light aircraft). I'm not necessarily advocating it, but it happens. I don't normally use one in a PA28, but then I've got thousands of hours in a PA28. I do use one in some other aircraft I fly.