Boats, boat trailers, or travel trailers may not be placed, kept, or maintained within the front yard areas of any residential (R) zones, except that such boats or trailers may be located anywhere on the lot, except in a clear vision zone of a corner lot as defined in Section 14.34.100, Provo City Code for a temporary period not to exceed twenty-four (24) hours for loading and unloading purposes, or for temporary storage not to exceed seven (7) days if such facility is owned by a bona fide guest of the occupants of the premises.