I don't know that I'd call it 'self-preservation instinct' but it wouldn't surprise me if rules had been hardcoded about 'invalid strings' and suchlike. When y

I don't know that I'd call it 'self-preservation instinct' but it wouldn't surprise me if rules had been hardcoded about 'invalid strings' and suchlike. When you have a system that can produce essentially arbitrary outputs you don't want it producing something that crashes the 'presentation layer.'