Three advertising aircraft crashes in three weeks. Odd?

In the past three weeks, two airplanes and a helicopter have crashed in the Long Beach/Los Angeles area. All three aircraft were towing advertising banners. The latest crash was today:
...Long Beach Fire Battalion Chief Jeff Reeb says the ad banner apparently became snarled when the Bell Jet Ranger helicopter crashed.

The pilot, who was alone in the helicopter, was taken to Long Beach Memorial Hospital. Reeb says he is expected to survive.

Last month a pilot who was towing a banner walked away from a crash-landing when the high-wing Piper P-A-18 came to rest upside down near Rancho Palos Verdes.

The next day an ad banner came off a plane in Long Beach and landed on power lines, causing a power outage.
If that isn't odd enough, all three aircraft were (according to KFI) owned by the same company.

At this point in time I'm going to assume that something else is going on. The only question is why the FAA or some similar agency has not stepped in and started an investigation to find out exactly what that is.