The San Antonio ordinance prohibiting lockblades is supposedly only enforced against the "wrong type" of people. As long as you aren't the type to attract negative police attention, you shouldn't have a problem.
That is ususaly the case in most third world nations, or authoritarian places. Discretionary laws with discretionary enforcement. Even laws where it is known and expected that 90% of the population will break it on a regular basis, only enforced when the police or someone in government has a problem with the person. They have laws against things culturaly acceptable, expected and even done openly by the majority in society. Things which would be changed if generaly enforced, but because the only enforce it discretionarily it remains a tool to target a minority discretionarily without the same outcry.
In fact that is ususaly the status quo of restrictive unfree places. Mexico and many places of South America for example often have numerous unenforced laws that it is normal for the majority of the population to break without anyone caring. Yet the police gain the ability to discretionarily arrest most people and charge them with such laws if they don't like how they look, answer a question, or they speak about the wrong topics. So the people are unfree as a result because most have something that can be used against them even just living the culturaly acceptable and expected lifestyle.
So it is never a good idea to support or even be casual about discretionary enforcement of ridiculous or unjust legislation. That is a primary tool of unfree nations. Don't tolerate it in the US.
Answering the OP. Knife laws vary much more than firearm laws within states and around the nation. Even knowing state laws often is just part of the picture. Various counties or cities have various ordinances against different weapons with different definitions of what constitutes a weapon or violation. Or what locations they are prohibited. For example one town may ban knives of certain features in general, while another may ban knives with different features in certain parks, playgrounds or other county locations while they are legal elsewhere. The locations and the prohibited features can vary tremendously from jurisdiction to jurisdiction.
The firearm community often fights to create gun laws that are more consistant statewide encouraging preemption and other things. That is often lacking for knives and other weapons. As a result you can have different ordinances in every city, and different ordinances in every county. Sometimes those ordinances trigger a state law against illegal items (which are not illegal at the state level, but when triggered by a local ordinance are an offense that can be punished under state law) which can be punished as a more serious offense.
