Dina Lohan isn’t afraid to show up uninvited. Lindsay’s mom crashed Saturday’s Art for Life benefit in the Hamptons. “She showed up with a friend and said they bought tickets, but they didn’t,” confirmed an insider. “Organizers seated them because they didn’t want drama. She was on a pretend phone call with ‘her publicist.’ ” Once inside, Lohan didn’t lie low: She asked a guest to move so she could put her purse on their chair. “My Prada deserves its own seat,” she was overheard sniffing. While posing for a photo, she told a guest, “I don’t have Instagram. My daughters do. They post pictures of themselves all the time. I’m like, ‘OMG, stop doing that!’ ”