no. you can easily spot a cameo if it passes by you on your bus
ride home. you don't really have to delibrately spot cameos. they
are everywhere. 
in fact,
when you are expert enough, you can recognise a bus and its rego
without seeing the rego itself but seeing other features like bus
ad etc. and storing a cameo u've seen can be as easy as typing it
out in ur mobile etc.
940M on
72
this 34S duty bus will arrive at Yio Chu Kang Ter at 5.17pm and
depart at 5.36pm. this bus was on 72 in the morning doing S shift.
the SBST computer showed 940M coming in to YCK at 5 plus, and while
chances are rare, hope it wun be replaced by a merc bus. expect it
to be at tampines at 4 plus too.