Monzo allows anyone to test, so that’s would be actually punishment for people, and not that good for Monzo as a product, in my opinion 
. Beta Monzo in Play Store is available easily, but I know there were some problems with iOS’s Testflight, cause all slots were taken. 
I’ve done my fair share of Monzo marketing in my social circle and I think I’m good with just this, knowing that they are using Monzo, making their life easier, and my life too - for sending money over.
Hugo had a Sneak Peak on something that touches appreciation area, that you might be interested in. Worth giving it a read and adding your opinion in there as well!