Spies are not planted. They are recruited.
To recruit a spy, is easy. U either compromise him, (eg catching
him having sex with an underage kid), bribe him with money, or
coerce him.
But handling the spy so that the operation is not discovered, is a
work of art. And of course, not to mention keeping the spy happy.
So it also depends how good the handler is at his field
craft.
IF a spy was to be discovered in PAP, then i guess there has been a
c0ck up on the side of the spy agency. Most of the time, through
leaks or spies in the spy agency itself.