There should be an option/setting/checkbox in the VRC Scene Descriptor to enable standard, expected Unity "Ignore Raycast" functionality. Raycasts such as the UI Laser and 3rd person camera should ignore the Ignore Raycast layer when this setting is enabled.
Having this as a user-facing per-world setting prevents the closure reason stated by Phasedragon on my last attempt to push this (see my old post "Desktop Interaction Raycast does not respect Ignore Raycast physics layer"). Note that this proposed solution requires far less complex steps to setup, and does not require the user to create a custom physics layer to replicate the purpose of a Unity layer, thus saving an entire user layer that could be used for something else.
It would be far easier to place buttons behind invisible walls (Something that I have done before) without desktop players losing the ability to click on them.
It would also make 3rd Person Camera functionality far easier to understand (as of 3p-beta build 1770, this layer mask functionality appears to be implemented, but with reserved3 instead of Ignore Raycast, and is undocumented. This proposal would fix this confusion as well.)
I believe a change like this will vastly improve the DX for every world that use invisible walls.