I'm in a rather disturbing conversation right now about making the sign of the cross. I won't go into details, save that it always seems like one of the main objections to making the sign of the cross in Lutheran circles is that people make a requirement of it.
Making the sign of the cross is a wonderfully pious and godly gesture in which the Christian acknowledges the blessings he receives and says, "Indeed, this blessing is for me." But it is not necessary, and anyone who says that it's necessary is living under the Law.
There are few things worse than making a Law out of something that is wonderful sign of the Gospel.