I had a situation recently where I didn’t uncheck the second box (didn’t know that was a thing) and did my final check in at the gate. Everything fine until my scheduled dh flight air returned and cancelled. When I called, CRS said I had deviated and am responsible to get to the destination. I explained it a couple times until I was transferred to duty officer. When he came on the phone, he just took care of the situation without me explaining anything.