Resources.LoadAll only accepts Path.AltDirectorySeparatorChar characters in the path. using Path.DirectorySeparatorChar fails.

if you try to construct a path using Path.Combine the Combine method uses Path.DirectorySeparatorChar to join paths.

Also a user could specify a path to a resource to load and they could type Path.DirectorySeparatorChar or Path.AltDirectorySeparatorChar.

This behavior is not in line with .net (and probably mono) behaviors.
Resources.LoadAll should treat Path.DirectorySeparatorChar & Path.AltDirectorySeparatorChar slashes the same.

Also the documentation does not mention this about using only Path.AltDirectorySeparatorChar characters.

NOTE: I did not test Resources.Load but I am assuming it behaves the same.