"but when the expenses are in the 10's of millions of dollars and that money goes to TPL...? "
What do you mean the money goes to TPL? The money to pay expenses would go to PDS in equal amounts from TPL and PTSC in order to pay for expenses incurred litigating the matter(s). I would assume/hope that our representative to the PDS committee reviewed said expenses with a fine tooth comb for reasonableness.
Where the real potential risk is involved, IMO, is whether TPL/Alliacense would negotiate a deal for less-than-fair value for the MMP, in return for better-than-fair value for their own portfolios/products.
Best