"Folding" is now interpreted to mean a knife which folds directly, without a lock. However, it's wrong to say that "anything with a lock is a no no". They are legal to manufacture, sell, own etc, and legal to use in public with reason (just as fixed-blade knives are; they've not been banned either). They are considered tools not weapons if you are using them as a tool.

(For the record, I live in England and own two of Doug's fine locking folders, and one of his fixed blades, quite legally. I wouldn't want a misunderstanding of British law to influence new US law.)