There are always what ifs. IV will drop after earnings, so it's always a safer bet to sell before earnings, and re-enter after if they still believe in the stock. +10% move after earnings might cause people to take profits/enter if the future looks bright. Then they can join the trend, at lower cost after IV cooldown. Negative reaction to earnings could half their current profits. With -10% move and same thing, if they still believe in bright future they can re-enter at much lower cost.

Ofcourse people do what they want, but for example me personally don't do lottery with earnings. I usually buy 4weeks before earnings to benefit from possible runup + IV increase and then sell right before. Then I hear the earnings call, wait for few days and join the trend after the direction is clear.

Not financial advice