How can we develop coding practices designed to protect against leap year bugs?

Microsoft has just announced that a software error in calculating dates (over leap year) caused a major outage in Windows Azure last week.

Was it really a simple error in judgement working around DateTime.Now.AddYears(1) on a leap year?

What coding practices could have prevented this?

EDIT As dcstraw pointed out DateTime.Now.AddYears(1) on a leap year does in fact return the correct date in .NET. So it's not a framework bug, but evidently a bug in Date calculations.