Have Mars rovers destroyed signs of life ?

Although I'm sure it's plausible to say the rovers may be inadvertantly removing any possible signs of life, I think the article is being a bit dramatic. The rovers only explored what would be the "tip of the iceberg" on Mars. There's a planet's worth of land yet to be explored that hasn't been touched by any human contraptions. Just keep the rovers where they have been already and everything will be fine.

What would be the point in that?

Image credit: NASA The Mars rovers may have been inadvertantly destroying signs of life in the methods employed to detect them it has been claimed. A new improved instrument for detecting life that should resolve the issue will be used in the 2016 ExoMars rover. "Have Mars landers been destroying signs of life? Instead of identifying chemicals that could point to life, NASA's robot explorers may have been toasting them by mistake." View: Full Article | Source: New Scientist lol, oops!

So are the perchlorate's somehow used in the identification process or are they there for some other reason? The article never says why perchlorate's should be suspected to be present in the rover or samples. Are they common? Ideas?