The idea of an 'exploding offer' seems a bit odd to me.

What makes it one-sided exploding? Are people being asked to actually start work in three days time, or just accept the offer?

What happens if you say 'yes' and continue interviewing? Does a big guy with a sword turn up at your front door and chop your head off?

Are people just trying to be polite and not burn bridges? Why would you want to be polite towards such a ridiculous employer?

'Negotiating' in this situation just feels really odd to me. Reply: "Okay, I can start in a few weeks' time". Phone down.

I am exceedingly uninterested in bending my life around employers - that's a world I left behind when I left my job as a retail clerk.