[wp-hackers] Uninstalling a plugin but keeping its options

[Dino Termini]

Hi all,

as I was saying in a previous message, I've developed a plugin that 
works in multisite environments. Following Otto's advice, I'm using 
add_site_option to store general (default) options that apply to all the 
blogs in the network.

Let's say this plugin is not installed network-wide, but just on some 
blogs in the network. The activation process will still initialize the 
general options, which is okay.

My plugin is programmed, of course, to remove all the options when 
uninstalled. But if blog A uninstalls it, and blog B doesn't, the former 
will cause the general options to be deleted from the database, thus 
creating an inconsistency.

How can I make sure to remove those options only when no other blogs 
have my plugin installed/active?

Thank you,
Dino