to be honest with you, not all bicycles will be stolen.
However, if your bicycle is of some standard............how you
lock also will get stolen 
That's why, i never bring any lock when i go out cycling. Lock also
no use one, sure kena STUN one
So my eyes always on bike & never
leave it unattended beyond 5 meters 
Got once at Rochor centre with my fren & our bicycles, fren go
into shop to see pouch, me outside guarding the nicycles, got one
uncle admiring our bicycles came & ask me, "Wah ur bicycle very
nice hor, u must lock properly if not sure lost. I tell him, uncle
u got see me bring lock anot? I don't bring lock coz this bicycle
even if u lock, people see will also cut the lock!!!
"
That time me alone at ECP, go toilet pee also bring the bicycle in
Anyway let me tell you my fren's bike specs, u
tell me u see u will stun anot?

Santa Cruz Blur 4X
FOX Talas
Shimano XTR Crank, Shifter, Front & rear Dee
Shimano XTR Hydros with red Goodridge hose & Saint levers
Thomson stem & seatpost
Easton MonkeyLite low riser bar
ChrisKing NoThreadset (Red)
Fizik Gobi
DT swiss 4.1d with Sapim CX Ray spokes laced on Chris King ISO Disc
Hubs (red)
Hope Seatclamp (red)
I think his bike is almost $8K & he still going to change to
SRAM XO shifters & rear dee 