I'm going to "borrow" your idea. I like the scraper you made and it doubles as a paint brush --- you might have an invention for an "as seen on TV" ad.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
Great I idea! I have heard that the sewer hose can cause the bumper to rust out. On my old camper I added a 4" PVC pipe with end caps and stored the hose in it. Debating on doing the same with the new one.
My old RV didn't come with a rear bumper so I made one out of a square PCV fence post. I put caps on the ends held in place by spring hinges. It worked very well and had lots of room. Of course it'll never rust.