The risk is HQ would handle it like any other organisation handling a public relations situation. They would assign a few people to deal with it and no one else really need know. They'll skim a few thousand letters over a few days and quietly put them in the bin and that will be it.
But if those same few thousand letters went to a few thousand KH's then there would be a few thousand elders wondering what to do and a few thousand calls to the branch and to the CO etc. and the effects would last for weeks/months.
I think it very much depends on the outcome you are seeking to achieve.
