Tyler Hamilton, a technology journalist from Toronto, has written in his blog about the practice of some retailers who still print full credit card info on sales slips. Check it out:
Tyler Hamilton: Why retailers are contributing to identity theft:
".... Word of advice: If you get a credit-card slip back from a retailer and notice that your full credit-card information is published on it, speak up. Let them know that's not acceptable, and that you may just shop somewhere else if they don't stop doing it. Otherwise, don't be surprised if you find some strange charges on future credit-card statements. "