The failure mode that is easiest to manage is when they completely fail.

Good luck to you with disks that fail silently over a long period of time, corrupting your data without you knowing about it.

Some correct fixes for this are combinations of RAID, backups, a filesystem that checksums data and metadata (BTRFS, WAFL, ZFS). Limping along on half knackered drives is probably one of the worst things you can do.

MAC address filtering is useless against a determined attacker. Your best bet is a WPA2 PSK with a long key, unless you fancy setting up WPA2 Enterprise.

Or, instead of thinking better of mugging little old ladies, Mike now carries a gun himself. Because he's a drug-addict, he doesn't adopt the same decent moral stance that you do on the use of guns. He's quite happy to shoot, because he's a used to an environment where little old ladies are legally able to pull out a gun and shoot him in the face.

It's my belief that by permitting guns as part of normal everyday society, an arms-race is started. The "bad guys" aren't worried about the legal use or ownership of guns (they're the bad guys remember, what's the problem with breaking just one more law!), so they're nearly always 1 step ahead.

Most cell towers are not omni-directional, they are segmented. It's quite common to have 3 or 6 separate segments on a cell.

It's possible to get quite an accurate arc depending on local configuration, from just a single segment. It improves significantly with two adjacent cells and dependent on the local configuration of the segments you could get a single location (dependent on whether the segment arcs intersect once or twice). The more segments per tower, the greater your chance you can pinpoint with just two towers.

By GSM, I also include UMTS.

From personal experience, I've seen none of these problems in the UK. Granted, our peak population density is about half that of big cities in the US (New York vs. London), but our national population density is an order of magnitude greater (1000 sq/mi (england) vs around 80 (USA) - or 650 sq/mi (UK) vs 80 (US)).

Seems to me that AT&T's network is just a bit crap. We have a bit more experience of running GSM networks over here!

Having said all that, O2 have had some spectacular cock ups on their data network recently, although not related to coverage/dropped calls.

So this thing is so advanced that it can time travel into the past and delay its own repairs?