@Linkat,
My catahoula and Border collie are bioth smart breed dogs and they are constantly testing "the bosses bounds". Theyve learned all the tricks that annoy me and use em to make points and get outside to work the sheep. (Thats like playing baseball to them).
My partner has 3 jack russells who, after he spent almost 5ooo$ to set up a silent electric training fence over his 5 to 10 acres (not sure how much he fenced underground. The dogs, after wearing the collars for a few days, discovered that if they got close enough to the buried fence , close enough to set off the buzz but not close enough to shock, they could run their little neck collars down and then they just skipped over the fence.
My partner then got one of the newer ones that shock and buzz at the same time (no training warnng). His dogs learned how to tear out each others batteries. The dogs have figgered out the fence like a pack of hyenas.