Out of the horses running, none of them will have completed Badminton. In the quest for qualifications, they went to Saumur, having retired on the xc. I cant imagine getting half way round the course before calling it a day due to a harmless rider fall or run out, and then going somewhere else, would cause any problems. Obviously a horse that got all the way round, only to be slightly stiff and unable to SJ the next day, would be very unlikely to come back out again so quickly. Most successful Badminton horses will be in their field, and brought back into work for Barbury etc at the beginning of July.
There were also horses at Chatsworth last weekend doing the 3* which didn't get round the XC at Badminton (and one of them was 2nd in the world cup qaulifier...). As Boss said, silly to have a fit horse and not go somewhere... and with it being a less difficult track might even be a good confidence building run whilst the Badminton mistakes are still fresh in the horse's mind.