There wasnt a safety briefing as far as i was aware, and i got there before the 10.30 time indicated on the email. The Tshirt was in the car, turned out to use my old series 6 t-shirt in the end. I wasnt wearing it only because i had just arrived and wanted to know what was going on.
Maybe it was a one off, but as it was my first time, i wasnt aware of their previous processes.