A concern I have with the valve at the end of the run is its freezing in the shut position (Had it happen twice on my last coach). Given that our coaches have such a long run of tubing running outside the belly I worry that my LM would freeze even worse than my SOB. Would make for a real unpleasant situation if one can not dump the tanks when needed. That said, I am looking at adding the twist on for now - I also get a small amount of waste water that comes out when opening that end cap. Luckily just gray water so far.