It's hidden in the bowels of the settings ...
Trapping it doesn't work Gareth because the standard all behaviour pre-empts everything. Technically, you can use the : do_all; command manually even when the standard all behaviour is disabled.
start_at = village locations {
village : location "You are in a village" ;
} objects {
lamp : object "a lamp" start_at = "village" ;
toaster : object "a toaster" start_at = "village" ;
} settings {
enable_standard_all_behaviour = false
}