That is extremely disrespectful to the country!
From the National Heritage Board:
The National Flag Guidelines
Singaporeans and non-governmental buildings may display or fly the
national flag to identify with the nation. Singaporeans are
encouraged to do this during occasions of national celebration or
national significance.
How it may be used
1. When the flag is displayed outside a building, it shall be
displayed on or in front of the building. Outside the National Day
celebrations period (month of August), it must be flown only from a
flagpole, and if it is displayed or flown at night, it should be
properly illuminated.
2. Within Singapore, it should take precedence over all other
flags, subject to international practice. When displayed or flown
with another flag, it must be in a position of honour. This means
it should be positioned where practicable, either above all other
flags or to the left of the other flags, as seen by a person facing
the flags.
3. It may be reproduced in reduced size representations and
displayed at all times, but it must be in its true form and
colours, regardless of size.
How it cannot be used or treated
1. The flag cannot be used:
(a) in any trademark or for any commercial purpose;
(b) as a means, or for the purposes, of advertisement;
(c) as, or as part of, any furnishings, decoration, covering or
receptacle;
(d) at any private funeral activity;
(e) incorporated or worn as part of any costume or attire; or
(f) on any private vehicle.
2. No person shall produce or display any flag which bears any
graphics or word superimposed on the design of the flag.
3. The flag should be cleaned when dirty, and replaced if it has
faded. After any washing, it should not be hung out to dry outdoors
together with other laundry. Any worn out or damaged flag should be
disposed properly, not left visible in dustbins. Torn or worn-out
flags should be packed into a sealed black trash bag before being
disposed.
