A /respawn command is needed when players spawn at Malibu sometime. To teleport the player back at one of his spawn points in the arena.

It could simply check if the player is inside Malibu and teleport the player back to the arena without any delay if true.
Malibu's Poly( 452.1610, -90.6330, 502.2740, -90.6300, 501.9740, -46.3090, 451.9360, -46.6510 )

I guess the problem would be at the bases which include the malibu, but I guess a a public message and admins online can prevent any death evasion or abuse.