In our brewery, our CO2 lines in every department (fermenting, aging, finished beer cellars) are all connected to a main CO2. If one department accidentally pushes beer into their CO2 line, it starts an emergency shut down protocol for all departments to shut off from the CO2 supply, until the affected CO2 lines can get pushed out and re-sterized. The bugs that can live in CO2 are nasty, and in our world we are talking about potential spoiling of 100,000's of bbls instantly.
So while we may go overboard, I wouldn't worry as long as you start with sterile CO2 lines, and don't get any beer back flowed into the lines. As well as not having empty lines sit disconnected and unpressurized for too long.
As well with StMarcos's advice, changing all the CO2 lines on a regular rotation will help prevent bio buildup.