- One should wash with a Bracha before eating the Matzah. The Mishnah Brurah explains that we wash again because it is likely that our hands have touched something dirty over the course of the Seder.
- If one know that one watched one's hands and one didn't touch an area that requires Netilat Yadayim one should wash without a bracha. 
- If one is sure that one watched one’s hands from touching something that requires Netilat Yadayim then one should rewash before eating Matzah without a Bracha. According to Ashkenazim preferably one should cause oneself to need to wash one’s hands with a Bracha. 
- The Chatam Sofer had a minhag to have others wash his hands for him to symbolize freedom.
- S”A 475:1
- M"B 475:1
- Chazon Ovadyah (pg 62)
- Beiur Halacha 475 s.v. Yitol. Halichot Shlomo 9:38 adds that Rav Shlomo Zalman would cause himself to require Netilat Yadayim with a Bracha.
- cited by Mikraeh Kodesh p. 283 n. 5