I have two different opinions on whether a clutch should be replaced when a slave cylinder fails:
It WILL coat the clutch plate and will wear the clutch plate. The clutch plate MUST be replaced. $1500
Even if it fails catastrophically, at worst, it will be 50ml of brake fluid, which can just be rinsed off with water (or hose pipe), and slave cylinder replaced. At worse, gear box taken off and bell housing also rinsed out.