Mana flags.

[IlPalazzo]

And healing life faster than mana does not promote camping?

Any aura/heal/buff you throw on a factory will promote camping. So yes, the higher healing rate does promote camping. Even more so that the end-game requires tanks to sit around idly to regenerate mana.

But - the general consensus is that camping is too powerful and attackers don't get much of an edge to compensate. It would be better to have the aura tacked onto an item attackers can use or for tanks to have a higher natural mana regeneration rate than to promote camping even further by buffing factory auras.