The DA can take the position that it isn't reasonable to expect people to leave their automobiles on a crowded road.
The statue doesn't require reasonableness, it deals with safety, just like the drafters wanted. Period.
Also, the word reasonable normally modifies something. 'Reasonable Person,' reasonable time,' etc. for examples. The way you're trying to use it, all by itself, makes no sense. (...Get your Refund...)
These laws have been on the books forever and are likely well settled.
Protests have also been happening forever.
This a not the case of, for example, new technology needing new case laws to be made.
Again, the onus is on the DA to show how his creative, off-label use applies via case law or other means. The defendant is innocent until proven guilty. The defendant doesn't need case law (as you stated earlier) to prove his innocence. Again, get a refund.