As far as the fog lamps. I don't really use them because they are always on. I have had other Pontiac vechiles that only turn on the fog lamps when the actual headlights come on. This car has them run with day lights as well.
I don't understand this but I've seen several different people write this as well. If you turn the fog light button off, they should stay off regardless of whether the headlights and/or DRLs are on. Otherwise you would be running with the interior lights on as well. On my GXP, the auto on/off will kick the headlamps on but not the fogs if the fog light switch is off. The only time the fogs come on "automatically" is if I had them on the last time I ran the car. There is a memory function to the fog switch. Short answer - turn the fog switch off before turning off the ignition. I think the problem is that there are two ways to activate the fog/parking lights, 1) by turning your light switch to half stop and using the fog button -OR- 2) leaving your light switch off and just pushing the fog light button. Pulling fuse 30 to disable the DRLs has no effect on this system.
Or do you mean that you can operate the fogs without the headlamps being on? If the latter I would think that is a benefit. Its highly annoying in Chyslers and Toyotas (among others) that the headlamps HAVE to be on before the fogs will work.
Also, I had the fog lamp forward harness replaced at the dealer and the bulb blew again. I replaced the bulb myself (a real treat) just to check it out and it hasn't blown since (+3 weeks). So, at least for now, the fix for the fog light problem works.
As for DRLs yes they will dim and brighten at what seems to be random moments. This is why I diasbled them on my SSE and my GXP. I've looked into this alot and have decided against having them for this reason (and many others). The light sensor system that GM uses is WAAAAY too sensitive. This is not just a Bonnie or GXP problem. If you want to stop this problem, pull the DRL fuse, but be warned that you will not have DRLs (which is a plus in my opinion, but other people strongly like them).