The Miller Park blog shares this
neighborhood soccer potty issue:
...a report from a neighbor who lives immediately adjacent to the lower Miller parking lot: she has witnessed players urinating in the bushes near the parking lot, because the outdoor toilets at Miller were locked.
Guessing that unlocking the bathrooms won't solve this issue completely. Show me a footballer who doesn't enjoy taking a leak in public. Hopefully the new field turf scheduled to be installed at Miller drains well.