Very effective:

On a macro and micro management scale the prescribed game fences do exactly what they are supposed to.

There are different classes of fences dependent on the goal and degree of containment needed.

In cases of Lion and cat proof fences the degree of containment is high vs that of a simple cattle fence.

To give you an example:

In almost 30 years we have not lost one single rhino. This with simple 7 ft 6 inch 17 strand game proof fence with 3 pulsed electric strands.

Break outs by a single bull have been a problem but in each instance the break out was known within a 12 hour period and in each instance he was retrieved untill his sale to another farm.

Now escapes and entrances do occur absolutely but on macro level the fences do contain game and if you understand territorial behaviour patterns you will know that the fence is not so much a physical barrier per se but a "training device" that regulates territorial boundries and behaviour.

This regulation of this territorial behaviour has been a subject of considerable debate amongst conervationists.
There is a global tendency to amalgamate properties into large conseravancies and in some instances even our national parks boundries are being extended across international borders.