Must an H-1B alien be working at all times?

In case you don't know and you want to take a long time unpaid leave, one USCIS memo states that " As long as the employer/employee relationship exists, an H-1B alien is still in status. An H-1B alien may work in full or part-time employment and remain in status. An H-1B alien may also be on vacation, sick/maternity/paternity leave, on strike, or otherwise inactive without affecting his or her status." (Please see reference: http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=a62bec897643f010VgnVCM1000000ecd190aRCRD&vgnextchannel=4b18dc4d88889010VgnVCM10000045f3d6a1RCRD)