Usually not, but there can be two occassions where this happens:
- I've seen situations in a mixed ESXi 4.0 and ESXi 5.1 cluster where DRS would move all VMs to the 5.1 hosts untill the host had 98% memory load.
- When you start with (or move) all VMs on the two hosts and there are still enough resources on those two hosts, DRS doesn't have to move any VMs. But I would expect that each new VM would be moved to other hosts.
Gabrie