It currently possible to soft-lock the game client using VRCPlayerApi.TeleportTo and Object.Destroy. The steps to do so are as follows:

1.) Use Destroy() to destroy the world spawn points. This will disable the built-in respawning mechanism.

2.) Wait two frames, then construct a Vector3 and a Quaternion with their components set to float.NaN. float.PositiveInfinity and float.NegativeInfinity work as well.

3.) Call VRCPlayerApi.TeleportTo() on the local player using the previously constructed Vector3 and Quaternion. At this point the game client will try and fail to respawn the player, thus leaving the client in a soft-locked state.

I have uploaded a world which demonstrates this exploit, which can be found here: https://vrchat.com/home/world/wrld_40311286-78ca-4cc3-a8b7-e78753366afe/info