A case study for everyone,:
Think abt HK, there r 5 bus coy(KMB, LWB, NWFB, CTB, NLB,
KCRC) are divided into sectors by operating rights jus like
SBST/SMRT.
However, bus svc of rival coy r common not in their home base
sector, like NWFB in Kowloon, which belong to KMB.
They even have joined operated bus svc(Cross Harbor Svc from HK
mainland to HK island)
Similar, Singapore could have Cross Territorial Bus svc by both
SBST/SMRT of the same svc?
Imagine Svc 160, 170, 950 jointly operated by SBST/SMRT. It will
be interesting.
But HK is big, not like Singapore, n they hav more ppl. BTW,
wouldn't having an SMRT bus on an SBST service (vice versa) be
confusing at times? It would take quite awhile for people to get
used to it.