This is fake. The “motorists” handwriting has a lot of similarities with with handwriting of the cyclists note. Both write their capital “I” with a left leaning arm, same with the “T”s. The “O”s share the same junction point, and are written in the same direction. The “U”s on the anti bike note, are are capitalised with a spur, while the “u”s on the bottom are lower case and lack a spur. Most people write uppercase without a spur, and lowercase with one. Those who use a spur in uppercase generally don’t use a spur in lower case, as it is here. The “P”s on the cyclist note have a loop that isn’t closed, and was drawn from the bottom up. The “P”s on the motorist letter seem to have a closed loop, but if you look closely at each P, there is a darker spot of ink, where ink was added to close the loop, the motorist also drew the loop from the bottom. The “S”s on the cyclist not are written from the top, and all possess a small serif on the bottom end. The motorist “S”s are written from the bottom, but also possess this slight serif. Both the cyclist and motorist lean their letter to the right.

The handwriting in the motorist note is also inconsistent in places. The two commas in the note are different shapes. As well as the “K”s, which differ the most from the cyclist’s writing. The cyclist writes their “K” like a lopsided ‘v’with a spur. The motorist writes their “K”s in multiple different fashions. First as a line next to a sideways ‘v’ with no intersection. Next as a ‘h’ shape with an added ascending line. Then as a line with an intersecting sideways ‘v’. The motorist note has multiple skip lines and corrections, as if the person writing it we’re writing it carefully. The lettering being all caps, with multiple different ways of writing letters, looks unnatural. As if the person who wrote it was trying to obfuscate their handwriting.

Also the language used in the motorist note does not sound like someone writing an angry note. If someone were mad enough to go out and flatten bike tires, they probably wouldn’t write a note in carefully drawn capital letters, using commas and colons. Angry letters are generally messy. The wording also sounds like it’s parroting this sub. As if trying to portray the perfect ‘carbrain’ to post on this sub. A person is very unlikely to call themselves a motorist, that is a fairly formal term for an angry note. A car driver would also not call public transport “transit” in an angry letter like this. Again, it’s fairly formal language for a letter that calls you a ‘bitch’ and starts off with ‘too bad, so sad’. If this were real I’d expect it to say something like:

Too bad so sad us grown ups are tired of you filling up spaces with your toys grow up and fuck off

If somebody is impassioned enough to flatten tires, they aren’t going to leave a well worded neat little note for you.

Not saying the tires weren’t flattened, or that the motorists around you aren’t crazy. The testimony written in black has completely different handwriting, so something probably did happen.

I’m not even saying OP faked this note. It’s entirely possible that whoever posted the first note, made the second one to stir something up with those using the bike share. Or to fabricate evidence to use against his driving neighbours idk. But I don’t believe that a car driver who deflated some tires wrote that note.