Again, these "HUSH" would be individually given and there are chances that, not even half of the forum would "HUSH" a particular user or even get to share with campaign managers and as such, it becomes statistically insignificant and might not appeal to campaign managers. How then do we work that?
That's what "S" is for. If you set S to 0 then "H" just becomes a simple ratio. If only 10% of logged-in users hush you, your H (for that activity window) is 0.1 and assuming that signature campaign managers adopt a system of scaling their payouts by 1 - H, you would receive 90% of your normal payout. If you set S to 0.5 then the same amount of hushes (10%) gives you an H of ~0.32 and your payout would be 68% of normal. Not many people have to use the hush system for it to be effective. I could see S being set pretty high initially, and then lowered over time if more people started to use it.
I'm not sure how signature campaign managers would get access to these "H" values though. I don't like the idea (not sure why) of having it be publicly visible on your profile, so maybe a forum-provided CSV file that gets updated at the end of each activity window? I don't think campaign managers would need much convincing to download and use such a file when issuing payments.