Glitch #1
Question #7 asked for the age and date of birthday. I don't want to spoil this for anyone, but if you know someone's birthday, you can figure out their age. Maybe this was a trick to catch people lying about their age?
Glitch #2
The census questions repeatedly asked about informaiton in the context of April 1,2010. However, the census was sent in early March, and then they sent along a "you better return that census" letter -- again before April 1st. Sure, I can calculate how old I'll be on April 1st, but how am I supposed to know who will be in my house in the future?