iPhone battery fail

My iPhone 3GS seems to be working well but with one small problem. Battery life sux.

The stupid thing lasts anywhere from about ½ a day to about about 1 day, which doesn't seem right at all.

I had also already jailbroken the the thing within the first few weeks of owning it, but since the latest firmware (3.0.1) came out recently, I thought I would update it in the hopes that Apple had silently fixed a possible power issue and to remove any jailbreak packages that could be causing this problem. No luck here folks.

About a week later I discovered that the phone was constantly emitting RF as a cheap set of speakers that I had turned on, would pick up the RF as interference and damn was this phone was being noisy!

After calling the Virgin Mobile iPhone hotline to get some support (which still didn't help mind), I stumbled onto apple's own iPhone battery information page and went through the troubleshooting steps, I seemed to have found the answer! Push mode notification. Turning it off has quietened it and the battery bar has stopped draining quicker than a cold beer in summer.

I am happy the problem is fixed and the battery is still in reasonably good condition, but this begs the question: Why is it on by default?