Always interesting when someone asks a questions and the answer could be used for a bad reason - and this seems like it could be that. Here is what you don't know:
This system could have a built-in cellular radio - lots of Protection One systems do. So, even if you cut a phone wire (if they have a phone line at all), the system would still be operational. And cutting power won't help, since pretty much all alarm systems have a built-in battery back-up that lasts for at least 4 hours, and perhaps as many as 24 hours. So, is it worth taking a chance? How lucky do you feel these days?
By the way, our company is 100% cellular, meaning that every system we sell has the built-in cellular radio, so no phone line is required. More and more alarm companies are getting on board with this technology. They charge more than we do, but at least they are upgrading from "old school" technology.
If you are a prankster or a bad guy, I hope you get caught.
With over 20 years in the alarm industry, I work for FrontPoint Security (www.frontpointsecurity.com), a leading nationwide wireless home security provider. Our company offers cellular monitoring and next generation features the “big boy” traditional companies have not figured out yet. I am offering this advice to increase awareness of what alarm systems can (and should!) do. The more we all know, the better!