Graeme,
Thanks for the warning. I'll try to keep that in mind.  
 
I am going to use the wall hangers for instruments I use less frequently than my main basses. Right now I intend to use them for my acoustic guitar, George Benson Ibanez and  Hagstrom 8 bass. My main basses I will be keeping on floor stands in front of the hangers. I've found over the years if an instrument isn't out where I can see it, it tends not to get played. So this is a way to keep them from being closet queens.  
 
Keith