Earlier quoted context omitted.
It's happening outside of schools. In my own network I know roughly 100 or so junior to mid level devs who have sought jobs in the last year and roughly 25% of them have dealt with exploding offers from NY and SF companies -- most frequently from the smallest and/or lowest-paying companies. One of my friends saw an offer explode in less than an hour. They had emailed him at 3pm on a Friday and had made another offer…
What makes it really fun sometimes is when a company ignores you or just dithers for months and months... and then out of nowhere comes at you with "Ummmm, so we'd like to hire you, can you decide in the next 48 hours?"
Even better than that is when you turn them down (for offer or interview) because you have another job already and then a month or two later you receive _their_ rejection letter saying that you're not the right candidate.
And I was an employee referral that time -- thanks Mattermark!