"All seniors and non-government or non-union workers get theirs first." ??? I sincerely doubt this is true. Why would it be true, and what entity would implement it??? KMP/R sends the cash (for KMP) and shares (for KMR) to the brokerage on the same day (and at the same time).
Are you suggesting the brokerage holds onto the cash and/or stock longer for some investors (non-seniors, non-union workers or non-govt. employees) than for others? Why on earth would they do that?
For the record; my Schwab account posted my KMR shares (whole and fractions) on 5/13 (the payment date). My Wells Fargo account posted the KMP dividend on 5/13, and reinvested the KMP distribution at $73.36, which appears to have been an order placed at the opening bell, and filled shortly thereafter.