The point about making it look like a rubbish bike is really just based on the concept of
this bike is rubbish - take that one
so it does depend on there being other bikes very close
hence the point that even though all locks that are portable can be broken - but why would a thief spend time breaking a U-lock
when someone has left a bike next to it with a cable lock that they can break with a cutter in 1 second
and also the idea that the actual thieves are normally not clever people and do not know much about bikes
If you have a clever, knowledgeable well equipped thief with the time needed
then that is what you have insurance for
for the normal type - looking rubbish and being next to a nice clean pretty bike is the best protection
I think your average scumbag can be put into one of two catagories:
- Career thief - knowledgeable about their target, skillful and well equipped - looking for high value stuff to punt on
- Opportunist - less accomplished in all the above, just looking for something to use themselves or maybe flog down the pub / swap for smack
With the career thief the stakes are higher as they'll be after more expensive gear, while being equipped to defeat better security. Conversely your opportunist has much lower standards.
The principal of "best security, worst aesthetic" holds true for both; however reactions to stuff at both extremes of the value range will likely differ - a career thief won't bother with a next-to-worthless-but-functional bike with zero security while this is a gift for the opportunist; while the opportunist won't recognise a high-end bike with mediocre security, or even bother because they lack the knowledge and / or tools required to defeat said security.