We effectively maintain all the barclamps which we ship, no?  So at this point in time I'd say it's internal.  Even Crowbar's REST API is currently only consumed by code we control ;-)  (Although I expect some of our customers may end up using it eventually.) 

You're basically talking about one half of [Postel's Law](http://en.wikipedia.org/wiki/Jon_Postel#Postel.27s_Law), and when dealing with input which is untrusted or outside our sphere of influence then of course that's a great idea.  But the flip side, as mentioned in [some](http://trevorjim.com/postels-law-is-not-for-you/) online [articles](http://essaysfromexodus.scripting.com/postelsLaw), is that it can sweep other issues under the carpet, leading to unintended consequences.  And when it only concerns code under our control, personally I usually prefer to err on the side of strictness.

BTW, this is not a -1 - the code seems fine to me even though it doesn't exactly match my personal style.  It's fun to discuss this stuff with you though ;-)