From personal experiences I would certainly fit one.
When I put my rib package together I was advised (by a dealer) not to fit an isolator because apparently ECU,s don't like them, just connect from the battery direct to the engine starter solenoid.
I had a good day out, recovered the rib onto the trailer, sat with the family having a sandwich and brew, suddenly the engine started to turn over and I had no means of isolating.
It was a mad rush to find a spanner to disconnect the battery, by the time I had done this the starter motor had burnt out. I had to have a new starter motor and pump impeller fitted due to it being out of the water and running dry.
The culprit was found to be a loose connection on the starter solenoid.