if my cypherin is correct the you would only add 3 matches to the mat by going to round robin with 5 (10 total matches) vs a 5 man bracket (7 matches). Not a big price to pay for 6-8 brackets spread over the whole tournament. I personally wouldn't come to a tourament if i knew there was a chance of a 5 man bracket. They still get 4 places both ways, but the 5th place kid in the RR gets 4 matches vs 2.