Hot water zone

Tony1

Hi,
This is from Dan's guide:
Q: How about on the return side of the zone piping. Where does that tapping go?
A: Again, use any available boiler tapping below the water line (never return water above the water line). If you can't find a return tapping, return into the system system's wet return, near the boiler.

Q: Does it matter which side of the Hartford Loop I tap into?
A: No, either side is fine, just keep that return tapping below the boiler's water line.

Can someone please enlighten me? If you return into the wet return aren't you defeating the purpose of the Hartford loop since if the return gets a leak it will now drain the boiler through the zones piping if the outlet is below the height of the hartford?