I'm playing LMoP with my friends and while I read the adventure I notice there are multiple opportunities to join different factions, so I wonder what happens if a character has an alignment compatible to multiple factions? Can he join all of them? I'm aware that you can gain renown only for one faction at time and if you decide to gain renown on another faction, the one you switch from will go to 0 renown, but it doesn't look like it's harmful to just join several and then decide where to rank or at least I haven't found anything in the rules that would prohibit this.
Am I making any sense here? Thanks