I did some checking and turns out there was in fact a reasonable explanation though one I had never encountered before. Turns out he is part of an aerobatic team and owns the T-28B. He has a waiver from the FAA and an aerobatic box over the SPI airport to practice in. He is legal to do aerobatics inside the box with the towers permission as he is part of a T-28 aerobatic airshow team. They have a website:
www.trojanhorsemen.com I am just surprised with all the agricultural land around this airport that they would not have him practice in that area instead. Learn something every day.