Mine's come loose twice and there's a horrible looking big black blob under it where it was stuck down and which won't come off unless I get more aggressive with it (which I'm reluctant to do). This time, I used some epoxy just on the bit that slides into the main rail and then added some gaffer tape, to secure it but also to cover a potentially sharp edge of the rail where the two bits meet. It seems secure enough at the moment and I have it in mind to just keep an eye on it. There's a guy round the corner from me who only had his rail fitted a few week ago and the same part came off on his first trip away in the van - I'm amazed that Reimo haven't come up with a better method to fix it.