27 is way to small for a byte value that starts with the hex digit B.

You aren't wrong, but that requires asking the question is this hex value correct? There are mistakes I can see without thinking such as missing semicolons and there are mistakes that require me to mentally tell myself "check this value". I would love to get to the point where my brain notices that I flipped a hex character automatically, but I rarely have the chance to work with bytes and hex values directly.

If I see 345,345,345+123,123,123=578,578,578,578 I probably wouldn't notice that this is incorrect but once I decide to really look at it the three errors are obvious.

As I commented below, it's incredibly striking exactly because it betrays a complete unawareness of the logic behind these systems.

These aren't just funny codes, there is a whole mindset behind it. ASCII being grouped in chunks of 32. Being able to flip between uppercase and lowercase by flipping a bit. The history of upper 8-bit codepages in DOS.

And I didn't even comment on the fact that your "byte" uses 16-bit notation.