> Making a transaction this large is a security risk. It effectively establishes a billion dollar bounty for any party who can rewrite enough blocks to erase it.

This is incorrect. It creates a billion dollar bounty only for the sender if they want to commit fraud by effectively reversing the transaction and trying to double-spend the coins by sending them elsewhere.

Anyone with 94k BTC would probably be harming themselves by simply driving the value of BTC to almost 0 by performing such an attack. It would be extremely obvious to everyone once this transaction was reversed due to a chain reorg.