Case-insensitive formats for Data.Time.Format?

Hello all, Is there a compelling reason to not make the formats in Data.Time.Format case-insensitive when parsing? This would apply to the months, weekdays, time zone. (I see there are already two formats %p and %P corresponding (confusingly) to AM/PM and am/pm respectively.) What got me thinking about this is that I'm being supplied with dates on the format "26 DEC" which will not parse without munging. I suspect such situations are fairly common? Also, is there a way to have the parser assume a century of 20 with the format %y? Thanks, Bjorn