That seems like it ought to be straightforward to defeat without OCR. If you know that a particular glyph looks like the letter J, then you just need to parse the WOFF file, find that glyph's data, and find the character that maps to it. It's definitely annoying enough to deter a casual scraper, but there's nothing conceptually difficult about it.
You do need to determine the "correct" character code for each glyph, but there are lots of ways to do that, on a spectrum from manual to automated. And you only need to do it once.
You do need to determine the "correct" character code for each glyph, but there are lots of ways to do that, on a spectrum from manual to automated. And you only need to do it once.