Travelling to Bahrain via Causeway - Saudi Family Visit Visa

you can exit to Bahrain but when you are coming back you will be asked for covid 19 done in Bahrain as the one you used cant be reused to enter
new regulations

Saudi closed the borders last night so your plans may need to change.

Secondly, I do the causeway trip every other week.  Saudi immigration will NOT let you exit unless you can show them a Bahrain residence or visa....EVEN if you are eligible for visa on arrival.  The problem is not Bahrain but Saudi immigration.  If you don't have a visa then they will send you to a room where you have to explain to the senior officer, any genuine reasons for going to Bahrain.  Here, they send most people back.   Use search.  We have had many threads on the forum about people complaining that they were turned back.

So, If we both hold a valid bahraini visa, will they allow us to exit Saudia and enter Bahrain?

Yes

Really? The few times iv done it now this has never happened?

It used to happen to everyone in the past.

Now it is on the whim of Saudi immigration.  If you have a lower profession on your Iqama i.e. anything less than doctor, engineer, manager etc, they will ask.  Or if your passport is not from the western countries, they are likely to ask.

I get asked randomly every other trip and I have noticed it is usually only when I encounter a female immigration officer - they seem to be more mindful of rules & regulations (and they almost always stamp my passport which is a pain).