Batchmode rendering non functional intended or not?

Running a standalone build with -batchmode command line argument causes Texture.Readpixels to output gray frames with the following error message:

ReadPixels was called to read pixels from system frame buffer, while not inside drawing frame.

GfxDevice is set to null because of the batchmode argument but i still want unity to render frames without any window opening / user session / the system has a gfx card.

1) Is there a possible workaround to render in batchmode?
2) Is it correct that Texture.Readpixels doesn't render correctly?
3) Is this intended behaviour to not render anything in batchmode or is it a bug?