Wouldn't really be a problem, but when I make it two weeks, then someone will ask for three weeks next. ;P
Right now, logs date back one week - with the idea that you can still check on the weekend on what happened during the week. If you're not there for two weeks, maybe someone else should help manage the guild. Two weeks is a really long time for a guild to go "unattended".
Finally, if all fails, we can still reconstruct what happened using the item logs - so if something is missing, you can file a support ticket to ask.