Is it unreasonable not to thank a driver who stopped? Even though they legally and should stop?
I know people will probably say "yes basic manners" etc. as a driver, I never expect a thank you, and I certainly would never ever get annoyed if someone didn't say thank you (its an ott reaction imo).
Long rationale ahead, to preempt expected backlash on this...
Putting forward the argument that:
A) they legally have to stop. Do you thank everyone for doing things they have to legally do anyway?
B) saying thank you to someone suggests they are doing you a favour, but are they doing you a favour?
C) do drivers thank pedestrians for waiting patiently at the zebra crossing?
D) pedestrians have right of way when crossing a side road on their straight path, so drivers ever thank pedestrians who wait?
E) the deference that a lot of motorheads think pedestrians (and cyclists for that matter) ought to show them is an irritating suggestion that they are somehow more important than other road users just because they have the more powerful mode of transport - when in fact the Highway Code suggests equal if not priority to other road users.