Hi,
During our first visit to Japan last year, in Seki City we watched a demonstration of Iaido and tameshigiri.
At the end of the demonstration the sensei showed their katana to the audience, all were blunt as a thumb run along the edge proved.
The particular school, unfortunately I don't remember the style, always use a blunt sword, "a true swordsman does not need a sharp sword to cut", "the speed of the cut is critical".
regards
chris colman