The plastic ede I use only come up about 3/4 of the height of the brick - there is nothing to break b/c it doesn't stick up. It is purpose built for paver edging. You are right - the regular plastic bed-lining edging would stick up and be too weak. I used something like this:
http://www.laurelblock.com/brick_stop.html
But the stuff I used had flanges under the brick too, which I liked. Slipped it under and spiked after setting all.