I would assume that all locks with any kind of picking detection features are either traditional lever designs or pin tumblers with several sidebars. In both cases it gets somewhat bulky and is mostly used for safes, high security file cabinets and safe-like doors at high-security facilities. It is not something that is readily available in the format of small padlock.
Also, for traditional pin tumblers, distinguishing internal scratches caused by picking from scratches from normal wear is surprisingly hard (but be gentle with the tension tool, that can cause tell-tale mark quite easily). It is non-trivial enough that in most cases the LEAs do not even waste time with doing any forensics on typical locks in simple burglary cases.
Also, many padlocks can be bypassed without picking in various ways (shimming is probably impractical on most belts, but the latch mechanism being accessible through the keyhole is very probable on such small self-locking padlocks).
