Hi C.A.
1. In 13 years of flying A320/321/330; No.
2. As several have said, to make it a subconscious motor program so your brain knows which ADIRU is which.
On my previous types: Dash 8's and BAe146's, if we changed the Alt, we would keep a finger on the FCU readout until the other pilot acknowledged the new value. Airbus SOPs require a vocalisation and acknowledgement of any change or new value seen on the PFD, so this covers the cross-check requirement. Some on other threads have said their company SOPs for flying Airbus do not mandate this vocalisation. I would say to those companies beware !