If all you have is standard wirenuts, try filling them with silicone caulk. It's pretty effective on small wire. Taping them is a waste of time. Keeping the wirenuts to the top is a very good idea.
The boss is the boss. It's his warranty and his reputation at stake. Sometimes the customer doesn't want to pay more, even if they have the money.
And yeh, every underground pipe and box will fill with water. I've seen the French drains (rock in the bottom) fill, and even those with sumps will eventually fail when the sump goes bad.
