I don't think its necessary
While some people may not be able to see the button, 95% of the people out there are able to see it. Given this, I wouldn't find any support to change the way it is now.
A single grey / translucent back background should fix the problem
That would take away from the design of the site. Aesthetics are important, and adding a grey or translucent background to the button takes away from the aesthetics (it looks ugly).