Your post is rather confusing. Hand bagage should not go out of view whilst being inspected. i.e. you should always be able to watch someone going through your personal effects. The reason for this is so that there is no dispute if something is found. This rule is very strictly enforced at most airports.
I do not recall my passport ever going out of my view. Of course I exclude the time when items are travelling through a scanning machine.
I use BKK airport roughly once or twice a month. I have never seen my bags being inspected out of my view. Thats going through the fast track and normal security lines.
Not quite sure what your point is Chris_S, but I have absolutely no issue with the staff at BKK airport, who could teach BAA staff alot in terms of Customer Relations and politeness.