The foggy look of memory lane made the google search terms experimental: "t-shirt happenings, artists cutting t-shirts in public, t-shirt performance art" and sure enough, on YOUtube, the name of Adam Saaks championed the list.
Adam plays up the performance by choosing a woman from the crowd to work on who has an intently staring, angry-looking boyfriend. And he's so sassy with his provocative cuts! There are many more videos, often time-lapsed showing multiple cuts on a shirt from start to finish.
The weaving technique that he uses is called "ladderweaving." His variable is the length of the cut to create variegated, webby-looking shirts that hold together with very little knotting. Use this as a search term on YOUtube to catch some tutorials if you are interested in this "home-spun" idea.