Loot at your own risk.The former professional motocross competitor who is married to singer Pink posted a photo on his official Instagram account Tuesday showing armed men, some wearing bandanas and masks to shield the lower part of their faces, standing with a sign that reads, "Looters will be shot on site. PDC Posse.""It's unfortunate that some people take advantage of others in a crisis," Hart wrote in the caption. "While the (Malibu) fires have been burning, some locals have been fighting off and defending their property against the fires."Wildfires have ravaged California during the past week, with 50 people confirmed dead statewide, thousands evacuated and some communities destroyed.California braces for more casualties as Camp Fire death toll climbs to 48With a home in Malibu, Hart and his wife are among the celebrities who have been speaking out on social media about the wildfires.Liam Hemsworth shares striking photo of his home in ruins after Malibu firesConcerns over looting have grown now that multimillion dollar mansions have been evacuated and there's no power to arm alarms at the houses.Lady Gaga visits California fire victims"There have been sightings of looters breaking in to homes," Hart wrote. "Well, if you are a looter, think twice if you are heading back into malibu. #DefendYourLand #2ndamendment"Pink tweeted her thanks to first responders last week.Kardashians pay tribute to first responders at People's Choice Awards"Just need to say THANKYOU to all of the firefighters. All of the first responders. All of the helpers," she wrote. "The thing to look for in tragedy is all of the helpers. We're all so grateful for your bravery and selflessness."