Speaking as someone who wants an Ironman mode, and who flies in a Open under the "pilot ejection table" rules, I sincerely don't think this will be much of a problem.
When it comes to ship ramming, I'm very much of the opinion that if you're speeding by a station, and you're not maintaining situational awareness, you get what you deserve. When it comes to GSPies, I doubt most will be tempted to try their luck, because Ironman players tend to be difficult targets to kill, who can also shrug off loss, and ONE mistake on a GSPies' part will boot them from IMM. Too much effort, too little salt.
Plus, the original proposal included an eject button, which has the exact same effect as a non-rebuy in the game: spawn in a station the free Sidewinder. Only if you ride a ship down in flames will you die permanently.
Ironman as it stands is something you decide to do and action yourself via the table, so you can disregard any dodgy deaths accrued through eejit shenanigans.