I hike alone mostly, but if I am with someone else, we stick together. I've read too many stories of people who have gotten separated. Some stories have happy endings (a helicopter ride for the lost hiker), some don't (body recovery).

If you are with people who are newbies, less fit, can't navigate or are kids and you let them out of your sight, you are an idiot, plain and simple. My only comment would be "WTF is wrong with you?" Be an adult, show some responsibility, so what if you have to walk a little slower. Is walking faster worth losing someone, maybe for good?

If you are out with people who have no qualms about abandoning you, my advice is what the Arthur's Pass SAR folks gave to a hiker they rescued after her friends abandoned her in the middle of nowhere NZ-get some new friends.