Pot smokers are receiving tickets every year charging them with having pot on US property -- a federal misdemeanor punishable by up to six months in jail and a $5,000 fine. The charges -- which are frequently negotiated down to an infraction akin to a traffic ticket and a fine of up to a few hundred dollars -- typically don't result in jail time, but often do require at least one court appearance.

Not a big deal, but it illustrates one of the many issues Washington, Colorado and other states face in complying with last month's Justice Department memo that requires them to address eight federal law enforcement priorities if they want to regulate marijuana. Among those priorities is keeping marijuana use and possession off federal property, which is defined as land owned and operated by the US Federal Government: national parks, military bases and the District of Columbia.

At the end of July, at least 146 people had been cited in Washington for having pot on federal land and 135 had been cited in Colorado. Washington's figure is slightly below the same period for the past few years, while Colorado's is roughly on track.

Defendants say being prosecuted for having tiny amounts of pot on US land -- especially in Washington, Colorado and states with medical marijuana laws -- belies the administration's assertions that going after people who comply with state marijuana laws is not a priority. The DOJ first announced that position in a 2009 memo, though the fine print also made clear that pot isn't welcome on federal property.

It will be interesting to see how this issue develops as more states legalize pot in some form or another, but in the meantime, watch your back when on federal land.