I cleared pre start but was chatting to the start official and between the two of us we forgot to check my card.
For the first few controls I tried to air punch and failed, but noticed when I dibbed normally the unit beeped. I then had to dib the rest of the course normally. In this scenario I reckon SIAC punching COST me about 30 seconds! Luckily it was just me

I'm surprised that this hasnt happened to more people since I have never seen any info suggesting this was a potential issue.
I did notice though at the Scottish sprints the cards were being checked before being given out...