Sharing from my personal experience:
One fine day I myself had fallen in to this trap.
Being ‘n-4’ (LTM, BIG IP F5 iRule) is the condition to trigger SSC (static site contingency) on the LTM layer, I could kill apache on most of the web servers but last 7 or 8 ( I use windows laptop so mPuTTY is my guy to trigger them in parallel) and guess what! all load had eventually had fallen into those few.
I lost control , lost time as well I was having a superman attitude and never invited Network (NOC) to do so by logging in to BIGIP and disable the pool members, so whole time was a waste, and finally I had to invite them as a rescue.
LTM was on and off Intermittent SSC and sometimes good but mostly bad Ux.
We can debate - that high load on servers will automatically trigger a SSC, but that will be an worse effect (not an action!) and uncertain scenario where we won’t be playing any role and we are talking about a human being putting a certain and timely contingency..
Hence I recommend this to go at the LTM layer by someone deliberately … ALWAYS!