Well I assume that most graphics cards, including internal will enable the user access to at least some reasonable OpenGL compatibility (hardware), maybe not out of the box but surely they can
get it from nVidia, ATI and the like (especially those 2, and they are very common).

So at the very least we can refer them to get the applicable updates drivers from the appropriate card or on-board graphic manufacturer or driver support if they have issues.

So if we can't ship them, can we identify whether what they have is good enough, and if not can we accurately point them in the right direction to obtain them?