unless I misunderstood Barbara's response to the question [Can 2 different VMs in 2 separate Vnets in 2 x separate subscriptions within 1 Management Group have connectivity with each other?] No. You can't automatically connect 2 VMs or have a VM in one subscription be able to connect to another VM in a different subscription, evn within the same subscription, VMs live in subnets within Vnets and traffic from one Vnet cannot reach another Vnets by default, the 2 Vnets will need to be peered! Peering is a requirement for connectivity between resources in 2 different Vnets period.
unless I misunderstood Barbara's response to the question [Can 2 different VMs in 2 separate Vnets in 2 x separate subscriptions within 1 Management Group have connectivity with each other?]
No. You can't automatically connect 2 VMs or have a VM in one subscription be able to connect to another VM in a different subscription, evn within the same subscription, VMs live in subnets within Vnets and traffic from one Vnet cannot reach another Vnets by default, the 2 Vnets will need to be peered! Peering is a requirement for connectivity between resources in 2 different Vnets period.