Pro: The work of some companies results in very serious damage to certain regions of the environment. The trees in need of protection are, in many cases, hundreds of years old. Once they are destroyed, the ecology of the region will be altered, in unpredictable ways, for centuries.
Pro: Often the policies of businesses, as they have an impact on the environment, are protected by law, and all legal means for preventing their execution prove to be ineffective. 'Monkey-wrenching' is effective: it slows the cutting of trees by directly affecting those who do the cutting.
Con: Spiking and monkey wrenching put human lives in danger.
Reply: Spiking and monkey wrenching can be used with minimal threat to human lives. Those who might be endangered by these practices can be warned: for example, trees can be marked to show the location of spikes.
Con: 'Monkey wrenching' can result in serious damage to valuable machinery.
Con: 'Monkey wrenching' can disrupt the operation of a logging company to such an extent that serious financial losses occur.