Haha, don't worry.
I didn't take it with me to the ocean or beach - just got it for a few minutes for this picture (yep, California Games Lynx, btw).
I know salty air will hurt it, so I put it back. Didn't care about sand, as I could easily remove it in case anything happens.
But nothing happened - didn't even need to open it up.
BTW: You don't wanna know what this unit has been through already. It's something like a sturdiness test, basically