I don't think undecided is the correct word. For me, I'm in the preparation stage which is hopefully drawing to a close, thank goodness. Yes there are some that just go off and do it without a word, but others like to mull it over, see how it sits with us to figure out if now is the right time.
Many have had previous attempts and know how important it is not to get either caught or maimed. As we can't talk it over with people offline, websites such as this allow a much needed headspace to reach that final acceptance and resolution needed to go towards as peaceful a death as possible.