Sewer extension

we have an Outback and it's a pain to halfway crawl under the platform to attach sewer hose when we dump our tanks. I've seen the "sewer extension" products on Amazon, but wondering if you can leave these on permanently?  Will they work themselves loose when towing?  If you have to take them off when towing, I don't see the point of using them.....

Extension Sewer Adapter 10" https://www.amazon.com/dp/B000HDETOS/ref=cm_sw_r_cp_tai_cGSQzbR4KBQCP