I've been to Rotterdam at the beginning of this month and since then or June there was a new law introduced regarding opening times. Now coffeeshops are only allowed to open from 10AM-22PM
except for those six located on busy Nieuwe Binnenweg as Witte de Withstraat which are allowed to open from 10AM until midnight on Fridays and Saturdays.
I looked up the internet but didn't find a source but I can assure you it happened as I visited at least twenty shops and talked to several budtenders about it. All shops had signs on about it anyway! Needless to say all were pissed.
Note: I was told reason is supposed to be again 'overlast'. People drive to the coffeeshops park their cars in front of the shops, get in and out fast, slamming their doors and flooring the gas pedal so quite noisy according to residents.
Personally I don't buy that story as I know - not a Rotterdam thing really - coffeeshops in general care about overlast and in my experience they don't want cars parked in front of their shops(where there is No waiting mostly anyway) or people hanging around making noise. Of course there are always exceptions.
I do understand those resident a bit(especially as Rotterdam is pretty much of a buy&fly thing because most places are take-away-only)but to me it's quite an lame generalisation and I hope it isn't something from things to come nationwide. Another restriction anyhow!