Your Detective Waifu on the case! (Forgive me if this isn't accurate)
So I looked through their Twitter posts and noticed on June 24 they tweeted: "Nothing for today. Tomorrow though. Around 10m, stay frosty." Then on June 26 they tweeted: "League of Legends (US) #Offline #PoodleCorp". And this video, which was posted on June 25, is about Boogie2988's channel being hacked. There were also other videos discussing Boogie being hacked that were uploaded on June 25, so I can assume they hacked him then. This probably means they gives a sort of "heads up" that they're going to hack someone through their tweets.
They also tweeted: "Please don't send us suggestions, we have many projects in the works. Stay tuned and more great stuff will come. I assure you." Ok then… I don't know about you, but I'm going to keep tabs on their Twitter. If they really do give warnings about when they'll strike next, it'll probably be the best thing to do.