As with the /boot60 command, bootday requires that you enter in a reason for a daylong boot for a particular user.
e.g. /bootday Bill abusive
Issuing that command will exclude user Bill from Voobly for a period of one day. The reason why he was booted is because he was abusive-as you recall, abuse on Voobly is grounds for removal from the site.
Specific incidents of using a /bootday command vary on a case-by-case basis, though a general rule of thumb is to save this command for the most extreme circumstances of violation of Voobly’s Code of Conduct or Terms of Service. For more information on day command reasons, refer to that section of the orientation materials.