I confess that I stick a point protector/cap on any free end of a DPN.
It means moving caps around and pulling the caps in and out of my little handy zip bag (where stitch markers, yarn needles and my emergency save-the-day crochet hook also live). But it saves a lot of internal swearing. I’m so used to it that by now when I don’t have the right gauge needles for a small project, I’ll just use a pair of DPN with caps stuck on the free ends.
For public transit, I eventually settled on afghan crochet mostly. Little can go wrong. One does get odd looks as few people know what to make of the long hooks or the technique.