I posted something below from the manual i got online.. so i guess it only shuts off if you let go when the blades are engaged.. i thought it shut off the mower regardless of the blades being engaged.. my mistake. oh well. guess i better be careful on those weekend beer runs
2.4 SAFETY INTERLOCK SYSTEM
Operator must have the transmission in neutral and blades disengaged to start engine.
Release of Operator PresenceControl (OPC) levers will cause engine to stop if
transmission is not in neutral and/or blade drive is engaged.