I suspect so ... in other words it should modify the code in [CRS.__hash__](https://github.com/esc24/cartopy/blob/98fc2363b4bda91b5469f555fdfee31b2a0f7223/lib/cartopy/_crs.pyx#L181) which doesn't tie in with [CRS.__eq__](https://github.com/esc24/cartopy/blob/98fc2363b4bda91b5469f555fdfee31b2a0f7223/lib/cartopy/_crs.pyx#L151)?