That is why I'm confused. Just a bit further down the road, where a bus lane replaces the big white lane there is a solid line with the bus lane, but they still have a signs showing 'no left turn'. But further back big white lane but no signs.

It is just confusing.

In that case I imagine the "no turn signs" are probably legacy, or a reinforcement installed when the line was painted to help people deal with the novelty.

It should not be confusing: any solid line must not be crossed, no other signs needed. My driving instructor used to say lines on the road are like walls, you can go on the other side only where there are holes in them. Can't be applied literally of course, but conveys the meaning.

Is it like Mellingerstrassen in Baden?

https://map.geo.admin.ch/?lang=de&to...osshair=marker

AFAIK this is not considered a as solid white line. Furthermore it is no really white but a bit yellowish. Also there are no signs which would forbid left turns in either direction. And unlike Avenue Alfred Cortot there are no roundabouts. Which means you would have to do a U-Turn either here (https://map.geo.admin.ch/?lang=de&to...osshair=marker) or here (https://map.geo.admin.ch/?lang=de&to...osshair=marker) Nobody does as it is stupidly inconvenient and annoying to all other road users.

For big surfaces you normally have to use a Sperrfläche/Surfaces interdites. The big diagonal stripes, as they were used on Avenue Alfred Cortot. (https://map.geo.admin.ch/?lang=de&to...osshair=marker)

Note: You are allowed to cross a solid line which has dashes on your side.

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What?

I understood the thick solid line as a hybrid between normal solid line and Sperrfläche... But it's not described in the law, so I might be wrong.

Yes. This is a special case: when there are two lines, you must respect only the one closer to you.

Update on my wife’s ticket which arrived today by registered mail: Although I said goodbye to 450.00 francs so far to the lovely canton of Luzern (still think something from Zug will come as they also sent me a letter saying they were waiting for Luzern's decisions…), I am happy to report that I was “only” charged 150 for the penalty, and, 300 for the police officer’s time. The court (paperwork) decided was not a “criminal offense” and there was no mention of probation which is great, but, this has been forwarded to the Migration office, which hopefully wont give us much trouble when we need to renew our C permits next time. All in all, I am really happy, except for loosing the 450. (But since I thought would be more… this is win-win.) PS. Had a choice for two days in jail instead of the fees…

Was it "all-inclusive" and possible to spend a weekend there?

Out of curiosity, what would happen if you had nothing planned for the weekend and said okay? Would it go on the record or be recorded the same way as a fine? Guessing you won't be able to take your phone with you haha.

They would actually first start a pursuit before you can go to jail. They want money, jail costs money. If you are employed they can directly size your income. Your employer will be informed. Going directly to Jail w/o passing Go and collecting $200 is only possible if you live abroad. https://www.baselland.ch/politik-und...reiheitsstrafe

As far as I know the jail time in lieu of a fine has no further consequences. Not the jail time is relevant, but the actual sentence.