the owner of bct has around 5 mill worth of btc.. i dont think he cares about nem

Are you telling us that you know for a fact that 2 years from now 500 to 1500 unclaimed stakes would not be worth 5 million? Why should you give power to completely crash Nem to people who have access to BTT servers? This is nonsense. Set a short time limit and then destroy them.
Leaving them open means that anyone who has access to BTT servers can destroy nem someday by dumping 1000 stakes.
Before the coins are distributed, the fate of unclaimed coins must be decided.