How raw can a plum be picked and still ripen on the table?

I ask bc neighbors or others have come to our yard in the past and stolen most (90%) of the plums from our tree in northern Calif. Some have even taken bites out of the plums and dumped them in our driveway and sidewalk. Thus, I want to pick em ASAP (even if somewhat raw) but I do want them to ripen on the table (or in a paper bag).Any suggestions will be welcome.Thanks.