nd6 'stale' timer unreasonably long?

[Timo Buhrmester <timo%math.uni-bonn.de@localhost>]

Routing traffic from a moderately busy WiFi (~100 stations give or take), we encounter plenty of IPv6 adresses.  I'm going to assume that it's multiple adresses per device even, due to the IPv6 privacy thingymajig.  Anyway.

Our neighbor discovery cache ends up exceeding its limit (net.inet6.ip6.neighborgcthresh) leading to packet loss.  I don't understand why the lifetime for stale entries (ND_TIMER_GC) is so long -- 24 hours!  Why?

Do we really need to keep 5k stale neighbors for a hundred or so stations, when it only takes milliseconds of time to resolicit a neighbor should they decide to show up again?

Those 24 hours seems to be hardcoded, too:
nd.c:46:static int nd_gctimer = (60 * 60 * 24); /* 1 day: garbage collection timer */

Is there a good reason to keep it this long and/or not-configurable?