I did not check, I guess it doesn't matter. If you waive the signature, maybe it will reach USCIS one day earlier, if you don't waive, you have a piece of evidence to show you did file something. In general, mails do not get lost, so either one is ok.
【在 H*****u 的大作中提到】 : I did not check, I guess it doesn't matter. If you waive the signature, : maybe it will reach USCIS one day earlier, if you don't waive, you have a : piece of evidence to show you did file something. In general, mails do not : get lost, so either one is ok.