These are really options trades based on the last few days prior to expiration. I'd recommend reading "Trading Options at Expiration" by Jeff Augen where he goes into a lot of detail around this type of trading, and also dives deep into the options pricing behavior the last few days. In your examples, they were right after earnings, but they can really be any time just prior to expiration. A lot of his trade examples are using unbalanced ratio spreads where you are short more options than you are long, so lots of margin required. But it does get you thinking about some other strategies such as 1x3x2 spreads where you cover the extra shorts with further OTM strikes. But most of these trades boil down to a gamble of minimal price movement.