In case of a helicopter crash on a rig helideck you want to cover the deck wit foam, and the net prevents the foam from blowing off the deck.
Never heard such a lot of b*lls in my life. OK, so I have heard worse, but not on a "Professional Pilots" site!!
Nets are banned on helidecks in the GoM, and we are prohibited from landing on any deck that has a net. They get caught on the landing gear, and can result in dynamic rollover.
Nets shouldn't get caught on landing gear if they (the nets) are maintained at the correct tension etc.
Don't know about you fancy rig flying blokes, but on tuna boats you lay down fishing net or rope, so said helicopter with metal skids does not slid off said boat with metal roof.
Helideck nets are generally only used for helicopters with wheels as skids can still slide across the netting very easily. If the metal roof was coated with a high friction surface it would be far safer for a helicopter on skids.
Perhaps the circle is an aiming point for passing military jets!