Microsoft has inadvertently landed itself in trouble with the law, after a Zune marketeer was arrested at the South by South West music festival. Police in Austin, Texas arrested the man for sticking viral marketing posters all over the town.

A Microsoft spokesman told Engadget : "We can confirm that an employee of a marketing agency engaged by Zune was cited for hanging promotional posters at SXSW. We've launched an internal investigation and will cooperate with local authorities and festival organizers in all regards. Zune is committed to lawfully and respectfully promoting its products and services."

The unnamed employee apparently faces three days in jail, or three days in front of a judge.

This isn't the first time desperate Zune marketeers have landed themselves in trouble. Microsoft was faced with a landslide of complaints after an official Zune SUV turned up in a New York suburb last month and started playing very loud music to passers-by and local residents - at three in the morning.

Big noise, small sales

The Zune is currently the third biggest selling digital music player in the US with 3.2% of the market, according to new research by NPD . This puts it well behind its chief rival - the Apple iPod (72%) and the SanDisk Sansa (8.9%). Microsoft can take a crumb of comfort from the rest of the top five. Creative is behind it with 2.9% market share, and Samsung has just 2%.