My buddy, when building his home, installed typical 3/8" magnetic sensors on the top (towards the open edge side) on each door in his living, family, and master bedroom with no problems. He just ran the wire along the top of the door space covered by the trim piece and drilled a hole in the side of the studs for the wiring to the panel.
The only problem he had was when the top slide latch on one door wiggled loose (months of not being open and slight vibration of the door due to wind we are guessing) it caused the contact to trip (even though the door wasn't 'opened').
It was actually a good thing in the end as no telling when he would have found out this one slide latch was loose.
Also, it showed how 'layered' security can help with remote determining problems on notification of an alarm. For instance we could see the door alarm go on and off continually (strong winds that day) but the glass break and motion sensor in that room would never go off. Also, no other doors or windows showed any status changes.