I just realized I said it wrong (wrong polarity). I meant to say
"I propose just a simple check box which is to be checked if there is NO bushwacking or undergrowth more than 1 foot high."
This way not checking it doesn't change anything as to the way the system exists right now. So it is backward compatible.
Now obviously any system will depend on it being used properly. The fact that at times it may not be used properly is not a reason for not having it. The existing system is not always used properly right now but that is not a reason to abolish it. It still is better than not having it. Anyway a "NO Bushwacking" checkbox would be far easier to judge than the difficulty or terrain.
Some typical examples of intended usage is where the hide is in a paved parking lot, or concrete parking ramp, or in a building, or on a golf course, or softball field, etc. You get the idea. The hider purposely intends there to be no bushwacking whatsoever but he has no way of expressing that. A terrain of 1 doesn't mean no bushwacking - just that there is no steep hills. Now he can check "NO Bushwacking" and still specify a terrain.