There were plenty of vacant asphalt areas both near the entrances and back near the main level permanent bathroom spaces where these units could have easily been placed. Have been to other outdoor concerts where when a crowd is at maximum (as this one was), the facility management plans ahead and brings in rows of extra porta-potties.
What was NOT excellent was: the very limited bathroom facilities and the horrendous parking situation at the end of the concert. The view was excellent as was the sound and we thoroughly enjoyed the concert very much.
It had been 26 years since I last attended a concert here (back when it was the World Music Theater), but we returned here last weekend for a Florence + The Machine concert and had wonderful seats in Section 104, Row BB.