This evening for a couple of hours my house had a major drop in water
pressure while the water department fixed a pipe down the block.

Strangely, a bathroom faucet on the first floor started leaking hot water
-- a slow stream, more than a drip but not a ton of water. The kitchen
faucet did not leak, nor did any other fixtures in the basement or on the
second and third floor.

I assumed this was just a coincidence and the cheap no-name fixture the
previous owners had installed had just died at the same time, but nope. As
soon as the guys finished work on the pipe and water pressure came back up,
the leak stopped too.

Any idea why less water pressure caused a faucet to leak?