Widgets – Poorly coded?

Is it me or are a large number of widgets poorly coded?  Although they may look good on your site do they actually conform to any standard? As I’m still putting this site together I thought it might be fun to add a couple of good looking widget adding a bit of interactivity.  I grabbed the code for the Twitter profile widget and the Books Widget from LivingSocial.com entered the code into my sidebar and checked the results.  Well, they looked pretty good, but when I used the  W3C Validator I was astounded at the number of errors it brought up.  Now perhaps I’m being a bit anal, maybe its the autistic gene but I’m not even expecting strict compliance merely transitional.  So wouldn’t it, after spending so much time creating a good looking widget, only take a little more effort to add a little conformity?