Defacing San Francisco public property to promote your latest thing is a surefire way to engender some ill will (just ask the Biebs), and yet people keep doing it. The latest company to soil our (admittedly already soiled) streets is GPS dog-collar company Whistle — a fact not lost on San Francisco's 311 Twitter account.

"Please refrain from putting illegal posts on public property," someone with the initials JM tweeted at the company yesterday afternoon from the city's 311 Twitter account. JM also included a helpful explainer to just what, exactly, constitutes legal public signage. Surprise! Whistle's attaching of invisible dog leashes to lampposts and parking meters around town doesn't fall into that category. Neither does the plastering of ads to sidewalks.

A quick Twitter search turns up numerous instances of the illegal advertisement — demonstrating that some time and money was expended in getting these things up around the city.

SFist reached out to Whistle, and a spokesperson for the company seemed caught off guard by 311's claim of illegality. "We put out the posts to help spread awareness about National Pet Loss Prevention month and the fact that 1 in 3 pets will go missing in their lifetime," wrote Julia Waneka. "However, we were not aware this was unauthorized placement and are actively working to take them down immediately. We meant no disrespect to our community here in SF and sincerely apologize to anyone who was offended by the posters."

San Francisco city officials do not take kindly to this kind of advertising, as evidenced by the City Attorney's threat to sue Justin Bieber's record label last December after it plastered sidewalks with graffiti advertising the pop star's new album. At the time, City Attorney Dennis Herrera noted the record label could face fines of up to $2,500 per instance and explicitly condemned corporate exploitation of public space.

"This prohibited marketing practice illegally exploits our City’s walkable neighborhoods and robust tourism," wrote Herrera in a December public letter. "[It] intentionally creates visual distractions that pose risks to pedestrians on busy rights of way; and irresponsibly communicates to young people that likeminded lawlessness and contempt for public property are condoned and encouraged by its beneficiaries — including Mr. Bieber and the record labels that produce and promote him."

In the same letter, San Francisco Public Works Director Mohammed Nuru hinted that the city would go after any company that followed in the Bieber's lawless footsteps. “Our sidewalks in San Francisco are not canvasses for corporate advertising, and we have made that clear," explained Nuru. "Yet these guerrilla marketers believe they are above the law when it comes to blighting our city and we will take a strong stand against them.”

Whistle is based in San Francisco, and according to CrunchBase has raised $21 million in two rounds of funding. No word yet on whether the hometown nature of the offender will lead the city to go easier on it.

Related: City Attorney Threatens To Sue Record Label Over Bieber Graffiti