It's the same situation with shaders, if you don't check isAvailable() and shaders aren't supported on the end device, then you'll have a problem.
We already provide enough options, that we can trust the developers to do the right thing and implement checks and fallbacks if they really want to, instead of hand-holding them through every possible caveat.
Not to forget that vertex buffer is a OpenGL 2.1 feature, so we're still in deep legacy land here.