I bet they won't change for a few murders. Maybe they'd change for a lot of murders, a few huge drug scandals and another 9/11. In the meantime, they'll take a little bit of bad publicity, but there's too much money in untraceable phones. Look at the US: 10 times the population of Canada, probably 10 times as many crimes (duh), and prepaid phones are still a dime a dozen. The shareholders would slaughter any carrier who tried to dump anonymous prepaid.
A few easy markets:
* guys who don't want to be leaving phone records for anyone else to find.
* people who'd like to buy someone else a phone as a gift
* travellers finding themselves in a country where their existing phone doesn't work
* SPs who don't want to be giving out their real phone number or racking up huge subscription bills.
* Law Enforcement and Private Investigators. Love 'em or hate 'em, they do have a place in society, you may need their services one day, and they sometimes need a new phone number, quick.
While I have no firm evidence to back up my suspicion, I'd guess that you're more likely to be injured wandering along parts of Hastings or Kingsway after clubbing one night than you are from someone ostensibly looking for a discreet rub 'n' tug.
I'm not faulting you for taking security measures - I'm hoping to provoke everyone who is taking security measures to make an objective assessment of their exposures, and make an honest examination of their precautions to see whether or not those precautions are doing any good or if they're just feel-good posturing. Of course, a really good security plan involves CCTV cameras, never having a moment alone, never having random visitors and having a squad of SAS officers on overt and covert protection detail, but where's the fun in that.
Back on topic: if you're running win2k or winxp, turn off the friendly login screen, and require users to type their username and password at the login prompt - don't let one user see what other users exist. Create a separate computer account for your shady activities, and delete and recreate that account every so often. If you spend some time setting permissions properly, your shady user will be completely sandboxed and it'll be easy to wipe that out. Turn on encryption/privacy for your users - this requires that you run NTFS. Run antivirus/antispyware. Don't do anything other than send email, read perb, or maybe chat a little from your shady user account. The last thing you need there is for some bit of spyware to be leaking your activities.
For more tips on securing your windows machine and preventing one user from messing with another, check out the NSA Security Configuration Guides:
http://www.nsa.gov/snac/downloads_os.cfm?MenuID=scg10.3.1.1