Years ago switchblades were popular with the wannabe thug youth. It seemed to be a fad. We found a ton of them on weapons checks after apprehensions. These were mostly cheap versions, many not functioning as they should. Lots of the thugs couldn't even explain how to use them. Mouthy punks had them for show. The older thugs would at times have knuckles, but rarely. Both when found looked like the cheap stuff you could buy in TJ. Now, some of the more established subjects, for example affiliated with MS13, they had very functional switchblades, well maintained and customized. You had to be careful with those types. Quiet and fast. Same with some of the day laborers that would hang around parking lots. If they were not picked up for work by 0800 they tended to get drunk and rowdy. They could be very unpredictable during apprehension, and often had nice switchblades. So, awhile back in my experiences switchblades of various quality were more popular than knuckles.
The one thing you could find on most though were throwaway pocket guns. It was a fad at one point to have Ravens, Brycos, Jennings, etc....with the grips taken off and wrapped with rubber. It wasn't uncommon to respond to an apprehension where bicycle inner tubes were stolen and the subjects provided admission to cutting them up in strips to sell to the gang bangers.