Just did this to my Multi but sure it will work on the most single arm bikes. It came about after seeing vids of the neds cutting off the front wheel disc lock so easily and noting the rear disc on single arm bike is quite inaccessible. I bought a suitable padlock and found a suitable location on the disc to fit it but sods law the spindle wouldn't fit through the hole so I enlarged it and one directly opposite it ( for any balance issues) Then deburred the hole. This means that the bike would be more difficult to steal which is always a deterrent .
A very valid point you have there, and a good idea, just make sure you make it visible though so might be thieves or muppets can see it as they might not and try to wheel your bike off which could cause serious damage to the surrounding area which would be a pain for you. Could you not have used a regular type instead?
Most front disc locks are too large for the job and you could make it more visible but not sure if it would have any effect, better them being taken by surprize when trying to wheel it away. You will never stop the determined scrot stealing bikes, better having a bike with a few scratches than none when speaking to your insurance.
If you were fortunate to have your bike next to another desirable bike that was easier to steal, imagine how you would kick yourself your bike was damaged due to the thieves not realising the rear disc was locked? A rattle can of florescent paint is a fiver. Its a good idea though.
It's not just the question of cutting, but even without cutting it off, two scrotes can easily lift the front wheel off the ground and wheel the bike out of view, coming back later to deal with it. It is less easy to lift the rear wheel off the ground in the same manner, especially if the steering lock is on which will prevent them wheeling it away. Immobilising the rear wheel means they have to physically carry the whole bike - not impossible but certainly not easy. I've always put my disc lock on the rear wheel.
