Eh, I think the actually did better there than they usually do. The flat faces helped the blocks stick.Why Scrap Magnets still sit in EXP: Check Community Core, presentation of Scrap Core.
Quoting Kris: "*laugh* That's why it's still in EXP..."
The blown up tech is the mortar explosion's fault, not the scrap magnet. The magnets can easily attached away from the guns to prevent that from happening.