[philosophyguy]

I like the Unwilling/Grudging modifier idea.

Here's another idea (which unfortunately I have no idea how to cost): give a bonus to Influence rolls using fear-based tactics, but also increase the threshold for critical failures (e.g., 16+ is an automatic critical failure). On a critical failure, the subject responds with a Disastrous reaction.

I have no idea how to cost it or how to determine the critical failure threshold, but it captures the volatility of the reputation.