Launching attachments on Windows?

I am making slow but decent progress on the patch to launch attachments 
from Pan, so far it has been easy thanks to gnome-open, kfmclient exec, 
and shellexec (I have been struggling a bit with tmp file handling but 
it is well documented so I should have that under control once I stop 
being distracted by the Super Bowl) but I worry a bit about allowing any 
attachment type to be opened especially under windows.

Should we protect users and not allow certain filetypes to be opened 
from within Pan?  For example executables, scripts etc...   For windows 
this would be easy if the file ends in exe, cmd, bat, scr etc pop up a 
message saying that Pan does not open Executable files and that they 
should be scanned for viruses before being opened.   How do we handle 
this under Mac OS and Linux?

Or should I just restrict the ability to open files to Media files such 
as images and text files since Pan will prompt people to save large 
files anyway?

Thoughts?