As the Moscow Times reports, the KGB is afraid, very much so in fact:

Although satellite navigation systems are widely available, their legality remains unclear, with some industry players insisting they are legal and others calling them illegal. NavMaps negotiated permission separately for the use of the maps for BMW.

Nine years ago, the Federal Security Service detained a U.S. engineer and charged him with espionage, saying he had taken land surveys of restricted sites using illegal satellite receivers and brought the equipment into the country without disclosing it to customs inspectors. Richard Bliss had a GPS unit with him for laying out a commercial phone system in Rostov-on-Don for his employer, Qualcomm.

Almost a decade later, the law, a holdover from Soviet times, still forbids determining location to an accuracy of more than 30 meters. This means that getting into trouble for using highly accurate GPS equipment is not improbable, although it is becoming less likely as detailed maps are now available on the Internet and Russians are becoming increasingly technologically savvy.
A Western European biker, who asked that his identity be withheld, said he had to hide his GPS when he traveled through Russia recently.

"I didn't want any troubles," he said.

The Defense Ministry, keen to further develop the Global Navigation Satellite System, Russia's answer to GPS, said in March that it would ease restrictions on location determination by year's end. The industry hopes that will further boost the use of the navigation equipment in the country.