gEDA-dev: hole to hole spacing?

[Dan McMahill]

Anyone ever come across design rules on minimum hole spacing which is 
more strict that just the minimum copper width?

I'm wondering if pcb needs to check this.

Part of this has come up because currently when you load a board if you 
have 2 vias whose copper is touching the 2nd one will be dropped.  This 
has caused some grief among users.  This is especially annoying because 
you can move an existing via that close to another but when you reload 
the board it will be gone.

One thought I had is to allow vias to touch but include a DRC check for 
minimum board material left between drill holes and possibly minimum 
center-to-center spacing.

Thoughts?

-Dan