The big NG pipelines extending north and north east from Texas, Oklahoma and the Gulf Coast were built during WWII or shortly thereafter. They are still in use. There's no reason to believe that the interstate lines actually have a determinable life span. Repairs and replacements of sections are ongoing.
Gathering lines have a life tied to the lives of the production fields. They are smaller diameter pipes that are known to have somewhat determinable lifespans.
Its "distributable" cash flow that is paid out. Other portions of cash flow are retained to handle necessary financial committments.
The "limited" in limited partner means something. Good luck hauling tens of thousands of unitholder int court. there are probably some circumstances where linited unitholders could be liable. Illegal activity would seem to be a condition allowing clawback.
Limited partners are just that. Limited to the extent of their investment in the partnership, i.e. what they paid for their stock. The GP is liable for losses in the partnership, not the LP's. Below is an excerpt from Wikipedia defining a limited partnership.
Like shareholders in a corporation, LPs have limited liability, meaning they are only liable on debts incurred by the firm to the extent of their registered investment and have no management authority. The GPs pay the LPs a return on their investment (similar to a dividend), the nature and extent of which is usually defined in the partnership agreement. General Partners thus carry more liability, and in cases of financial loss, the GPs will be liable.
I wrote earlier on these posts about these types of companies that exist by continually rolling over debt. I wrote favorably about it:ie. think AT&T, Verizon, all the big Utilities, how my father used to run his restaurant(I told about that example). I know it is alarming right now hearing about all that Kinder is doing in this process of absorbing El Paso. But we have to trust the management on this and wait for everything to be resolved. I am going to do a new post on the Regulators involvement in all this because I want everybody to take notice.