Thank you for information @Thijs ,
I am not so sure everyone would be fine from a security point of view not to use some kind of verification when you execute disposition activities like approving an iDeal payment.
I personally do not mind additional security which is easy to use like iDeal approval workflow. Maybe it could be set as an option to disable if someone is interested... especially when making a lot of payments in a day.
Another verification option, which is available on recent Macs is to use finger print ID to validate actions.. that is also very secure (probably secure as iDeal process).
thank you a lot