By the way, while Silvia's diminutive size and at-will Invisibility render her fairly undetectable by mundane means, I'd like to note that neither Invisibility nor the Stealth skill provide any protection against Detect Evil.  I'm not saying to find some pretense to use it right away, but if you find yourself in a situation where you are using it and Silvia is within range, feel free to just automatically detect her in your post. ^^