Yes, while the odds are it is the seat switch, you need to post what tractor. I never 'assume' the tractor IS the one in your 'info area' or whatever you call it. Several memebers have LOTS of equipment list there but need help with one specific unit or even a neighbour's totally different tractor.
One thing about the seat switch is that there's a small (1-2 second) delay from say 'standing up' to when the engine shuts down. This is normal. If it cuts out faster, there may be a wiring or other problem.The more info you post, the better we can help.