Specifically, turn off data roaming. (Wi-Fi is fine.)

A trip to Canada in January netted me a $3k phone bill. $3k to use Rogers. There's a few Canadians snickering at the thought right now. ;)

For others in this situation: a call to customer support saying, basically, "OMG three thousand WTF?!" got me retroactively switched for the month to an international data roaming plan; I ended up paying the difference in cost to upgrade, which was still a few hundred, but after you've seen the $3000 phone bill, a few hundred bucks looks pretty good. I also learned very clearly: turn off data roaming, or make arrangements in advance to switch to an international roaming plan (wouldn't have been practical in this case, but would have been for a planned trip).

however the idea of sensors inside your portable devices detecting what you do with them might raise eyebrows even beyond the tinfoil-hat community

Bought an automobile in the last few years? Then you're probably already living with this.

Excellent point. Just to head off other people talking out of their ass (wishful thinking, I know), the pinout for the iPod/iPhone connector ought to be required reading before commenting on what it can and can't do. That connector provides interfaces for USB and Firewire, audio in/out, video out (composite and s-video), serial, and dedicated power.

It's not an ideal situation, but a single cable covers just about every possible use case. That's a big deal, ergonomically, and it means Apple can standardize internally on an interface across multiple product lines.

It's unfortunate: the knee-jerk reaction to "we need a universal charger" will miss the opportunity to standardize on a SINGLE interface cable for mobile devices, rather than using USB for power and data, a headphone jack for audio output, and who knows what proprietary arrangement for audio input and video output.

My wife had no idea what I was talking about when I made a comment about that a week or two ago. Ahh, "Vignettes". ;-)