Is it safe for a gecko to take a small trip in the grass ? You know, gecko DO lives in the wild ! Can he be bitten by a bug, yes he can, can he eat a leaf of something, yes he can...and this can goes on and on. I really think that the risk is moderate, and he really seem to enjoy it. And by the way, in a normal enclosure, there is a risk of fire hazard, there is a risk that your house crumble with an earthquake, that you die of an heartattack and your gecko starve to death....A risk free environment is impossible. It's just a question of evaluating the risk.

-----
Mizar 21
1.0 Collared lizard (Ganymede)
1.0 Leopard Gecko (Gethsemani)
1.0 Nerodia Fasciata (Serpentard)
1.0 rescued iguana (Gomez)
1.2 Cats