As Scott said, they should not blow out.
Take them back and be nice
... but here's what is going on:
When finished servicing the units, they should be pressurized, and then the environmental seals should be installed, then when turned off and purged the seals will suck back in. Therefore they will not blow out... unless they put the seals on without pressurizing the regulators first.
They reallty don't have to go back to Zeagle for this. It's very common and easily fixable.
To put things in perspective, if they were not environmentally sealed models there would be no issue at all.
Chad