I did find this in gconf

gconftool-2 --type bool --set /apps/modest/accounts/AccountID/enabled

and

#gconftool-2 --type int --set /apps/modest/update_when_connected_by

I'm getting closer to finally stopping this.

Modest will pop in just for a second now, once a minute, then disappear. So it's gotten much better.

Setting the interval to 0 didn't work but that was a nice idea though.