Some purchasable items are marked as "dangerous". What this means is, if the setting "Confirming" is toggled, every time the player tries to purchase it, it asks for confirmation. This prevents accidental missclicks on buying these items.
Gigastation upgrade is marked as dangerous as it creates irreversible changes to the Warpstation. Gigastations are non-renewable until one portals.
If the player had reached zone 31 or further, Shieldblock becomes marked as a dangerous upgrade. This is because in the later stages of the game, the player should carefully consider whether they want it at all, as using health shield is usually a better choice. Shieldblock cannot be undone.