Every guild is different, and every player is different, and no one can (or should) force their rules on anyone else (or any other guild). What works for you or in your guild doesn't necessarily work for someone else or their guild. In our self-centered world, that concept is sometimes forgotten =)
Right now, a new member "on probation" is no different than an established member who knows the ins and outs of what makes the guild tick. Instead of a transaction log, allow the guild leader to assign permissions for who can deposit and withdraw items from the guild storage, regardless of in-guild title.
Then, once you are comfortable your new players understand the goals and directions of the guild, then you can give them extra permissions or send them on their way somewhere else if they don't really fit.
Right now, a new member "on probation" is no different than an established member who knows the ins and outs of what makes the guild tick. Instead of a transaction log, allow the guild leader to assign permissions for who can deposit and withdraw items from the guild storage, regardless of in-guild title.
Then, once you are comfortable your new players understand the goals and directions of the guild, then you can give them extra permissions or send them on their way somewhere else if they don't really fit.