What is the tracking priority when a customer visits our shop from URL?affiliates=1 and then from URL?affiliates=2 and makes a purchase?
Which affiliate will get the referral fee?
Is there always one affiliate that gets the referral fee or will both 1 and 2 get the referral fee?
The last referrer is getting the commission, in the example you mention, it would be the one with ID 2.
With some integrations, for example WooCommerce, you can have split commissions based on coupons.