There is really good reason to have it set to off POSii=0 , if this is now hard coded in the new wallet XMG as posii=1 its just asking for forks, The chain must be fully synced before the wallet enters POS.
Once a fork happens it is choas, exchanges lock down wallets, pools stop. Thinking I should look start looking different coins now if this is not addressed.
The staking is disabled before fully synced. It would be a mess that the wallet generates blocks while taking blocks from peers; and even you can generates blocks, they won't be accepted by the network as you just work alone. If wallet is stuck while sync, that's not due to staking but something about downloading blocks. In a case you get forked, you have to discard the whole block data and resync from scratch; would that be the case you run into?
And most importantly, it's not that easy to fork, as magi is PoW/PoS based; you got to work on both PoW and PoS for a safe fork.
Speaking of the setting, the PoSII is a lot safe in most of case by giving default 0 (PoS disabled). However, it won't be nice for general users cause they have to go editing magi.conf in order to enable staking, which is a barrier more or less, and sort of the confusing part. I'd vote for the other way around, easy to stake in general.
And don't forget, once wallet is locked by password, you're default not to stake.