EC2 instances moving in and out move the hashrate much more than the quoted 'spike'.
Let's do the math.
Top EC2 instance has around 700 hash/sec. One added instance is likely to have 42,000 difficulty increase.
To get 100,000,000 difficulty increase you'd have to add 2,380 of top EC2 instance. Each of the instances costs more than $1000 per month ($33 per day) and requires some work to increase the limits on your account and prepare the servers for mining.
Not only I don't believe someone invest $80,000 a day to mine XMR, it's very unlikely that it could happen in 2 days.
We can’t let viruses and trojans control the currency.
Yeah yeah, doing the best they can instamining the coin with silently updated hash function and FUDing other topics. lol.
Come on, give Monero guys some credit. They are maintaining the biggest CryptoNote community there is and doing it pretty well.