linking BSD and GPL code via a plugin

[Kevin Hunter]

Hello License List,

I'm confused (yet again!) about linking to libraries and other programs. 
  I am working with a BSD licensed project, and I've been tasked to 
write a plugin to call functions of a GPL project.

- The project will distribute the plugin, but not the library against 
which the plugin links.

- As I have currently instantiated the plugin, it sees if it can load 
the necessary libraries.  If it can't, it disables itself.

This will put the onus on the user to download and install the GPL 
library, which I thought was the point.  Then I saw this go by on 
another list:

 From another list:
> If they are linking to the [GPL] code or having Java code link to
> the [GPL'd] API then I believe there is a serious problem and the
> code that links to the GPL 3 code is then by definition covered by
> the GPL 3 license.

I continue to be confused on this point (as do many others, given my 
googlings!).  Here is my understanding; please correct it inline as 
appropriate:

I believe the issue is distribution.  As long as $COMPANY does not 
_distribute_ GLPK along with their proprietary code, they *can* write to 
GLPK's API.  Then, the onus is on the user to download and install the 
GLPK.  If the user decides to use GLPK for their own internal uses, 
there is no problem.  Since $COMPANY is not distributing the GPL code, 
all is well.

Have I blubbed that point?

Thanks,

Kevin