We sailed many years on a 24 foot raceboat that had no stanchions or lifelines. No one ever fell off the boat because the lifelines weren't there. Once you are accustomed to the idea, it's not so bad. In fact, I once sailed on the same design that had lifelines (due to it being a distance race and the rules required them) and they were noticeably in the way and sailing the boat was uncomfortable.
Many refer to them as "deathlines" given their greater likelihood of tripping you rather than saving you, especially on smaller boats.
If you and your crew are relatively agile and surefooted, and you're unlikely to be often sailing in particularily rough conditions you'll probably be fine without them.