My 2 cents: I think it is better not to store the muzzle bungee and spearline under tension - if you can live with all the line flopping around making a mess!
In practice I leave mine under some tension. With spear guns, especially newer models, it is possible to remove a little tension by not using the side flaps (newer spearguns) and by modify line routing around the muzzle.
Thinking about it now, I suppose there are good ways to store spearline not under pressure. For example:
* Remove spear and spear-line from Speargun. My Omer Spearguns each came with a plastic spear-cap/line winder for storing spears with spear-line. Those clever Italians! Leave the bungee attached to the muzzle.
Or
* Leave the spearline attached but not wrapped around the line-release. Perhaps release the spear from the trigger mechanism too? Then use small rubber bands (or sections of old bike inner tube?) Or cable ties to bring the spearline under control
