[johnrob]

You might avoid doing certain write-esque operations if you know you are in test mode. For example, you wouldn't want to charge a credit card or update someone's facebook status.

[praptak]

On the downside this might prevent some great dramatic literature from being created.

[Deestan]

That makes sense. It didn't occur to me that someone might want to run a monkey test in a live environment, but I guess it is necessary sometimes.