Can you rely on crowd-sourced mobile coverage maps?

http://cdn-static.zdnet.com/i/r/story/70/00/010111/coverage-620x542.jpg?hash=MQMyAmR2AG&upscale=1

How can you really tell whether your mobile phone provider is actually being truthful about coverage? Is crowd sourcing the answer?

As mobile data use continues to skyrocket, and mobile networks become more critical than ever, people are paying more attention to the sort of coverage they're getting from their mobile providers. The Telecommunications Industry Ombudsman (TIO) frequently cites coverage problems as being one of the most-complained-about issues with telecommunications companies in Australia.

Telstra, Optus, and Vodafone all have extensive coverage maps on their website that tell you exactly where you can get 2G, 3G, and in some cases 4G. But how do we know they're accurate?