As it is now, unethical AIs have a huge advantage over ethical ones.
Unethical behaviour always has a huge advantage over ethical behaviour, that's nothing new and pretty much by definition. The only way to prevent a race to the bottom is to make the unethical behaviour illegal or unprofitable.
None of the AIs have any 'knowledge' to begin with, so that's an easy one to satisfy.
There’s other options besides a blanket ban.