The officers talked about how long we would allow someone to "try out" our guild to see if they wanted to join. The time frame is 2 weeks. More guilds are raiding now and we did not want to have to worry about someone from another guild being able to come in and read our MOTD and then report back to their guild what our raid plans are. We don't want to feel like we can't talk in guild chat freely without worrying about a spy.
This was straight from the July officer meeting after a guildie got booted for having membership in BI, Static, VGE and was using VGE to gear his other guild toons.