Not sure if you've considered this idea or not. Big spenders, high rollers, and la-di-das can probably care less what I'm about to say-but it's something I am a little confused about. If you created a pure spy or pure attack build(osf and oaf) and never upgraded your castle could you open essentially? Castle upgrades add att & spy attack making the possibility of zero att or spy attack impossible. Grow an acct., max it out, never upgrade your castle, and never have to pay for hte? You could just sell pots to keep a little cash out and stay open as an osf or oaf. Tis' true or bahumbug nonsense?
The castle upgrades add static boosts, but have no troops. The mechs go off of troops, so a pure spy could be hit if it has gold out regardless of castle level.
Lol I had to make some revisions or it would have been derailed due to low effort. The idea is sound but not sure if it is true or not.