Michael, I assume you are joking - the reference to the sale of an illegal drug is IMHO inappropriate. The problems caused by too many people attending events at the Horniman have been well documented, suffice to say I miss the days when horse manure was freely available and you could the cross the road without fear of a speeding horse. With regards to the Book and plant sale, it hasnt been advertised in Gardener's World or the Libraries of South London, so I'm sure the park will not be over run by tens of thousands of non Kindle reading bookworms and green fingered gardeners.