I don't typically peddle my own videos on this sight but I everything you're being told about the 1911 is pure and complete bull crap..
Watch the above video especially around the 4 minute mark on which specifically goes in to "cocked and locked" carry and why it is safe (I go into EXTREME, broken down detail so there is no lingering question) including why you shouldn't have to worry about your hammer falling.. I won't retype what the video says because it would just take too darned long. After you watch it, go back to these guys who've been telling you all this crap and stick your tongue out at them for me.
That being said, for concealed carry of 1911s I only carry open top... have been since the moment I got my CCW permit about two weeks after I turned 21.