You know better or is your brain on vacation?
Come on, if you bother to look up the seat switch you find it a NC version. Plus the seat switch connector will already have a shorting strip to prevent someone from simply unplugging the seat switch. Putting a jumper in the connector does absolutely no good as the connector is already jumper-ed when unplugged thus keeping what would need to a open circuit when the operator is on seat, a closed circuit.
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And I have seen that 3 pole brake switch to fail open the kill circuit.