Jeroen 🏳️🌈 John
If it turns out to be a problem, they can of course try to come up with a solution that wouldn't involve changing the way it functions by default.
I created the account the way you describe: After I discussed it with support, I upgraded my own PROMO to Premium, created the account and then added the PROMO user. Thing is what they said made sense as well: as free users can send unlimited online transactions, promo users can as well - just card payments count to the limit as the cards are what makes it different from Free. It made total sense. :)
My primary concern right now is direct debits. If I make a card payment from the account, it doesn't count to the partner limit. If I make an iDeal payment, it doesn't count towards the partner limit. But the biggest question mark is what will happen with direct debit ("automatisch incasso"). That's the area of concern. If a direct debit takes place on a shared account, does it count towards the transaction limit of the PROMO user? And if so, what happens when their limit is reached whilst I have a normal premium account with Unlimited? The answer from support to that question was thus that it wouldn't count anyway as those are not card payments, and as only card payments count: no problem. You can see the dilemma here if they do count towards the promo spending limit, that would render any direct debit, be it direct or accumulated, exceeding the €250 limit impossible to execute which would render the whole account useless for that purpose. ;)
If those direct debits indeed do not count towards the spending limit as support said, the account is usable. It still sucks iDeal and normal bank transfers do count towards the limit, but that can be worked around without too much effort. But if direct debits turn out to be a problem... Well, that would pose a significant limitation that renders the account limited beyond what is acceptable. And I'm not about to pay €16/month just to have a single shared account... Nor €10 for that matter. ;) No the premium + bunq PROMO setup as advised by support sounded like an ideal solution. :) Even in a Pack that construction would still be about 4 times more expensive than other banks, but I can live with that and due to some of the features I'm more than happy to pay it. But if for direct debits to work the other party has to upgrade: then it suddenly becomes an extremely expensive shared account which simply cannot be justified. :P
Either way, we'll have to see - I haven't heard back from support yet about direct debit influence on the spending limit of a shared account opened by a Premium Unlimited customer. :)