They may be talking about the seat pads that are actually part of the seat and have become worn and unserviceable over the years, as opposed to people bringing things into the cockpit with them. That is something I've never seen in the Prowler community.
Brett
It might have been both, but the specific thing I saw in the message/email was about bringing your own cushion to the party. Ironically enough, there was a specific mention of T-34s, but they also mentioned other airframes, both helo and Tacair, because of the different reasons (seat stroke/ejection seat/etc). I think you're right, though, the reason people bring cushions is because the stock ones are cheap and wear out.