A DefaultTellTopic responds to any TELL X ABOUT Y command when no specific response (TellTopic or AskTellTopic) has been provided for Y.
A DefaultTellTopic is relatively easy to devise, since it need comprise no more than a non-commital response to whatever the player character chooses to talk about. Here's how we might implement a DefaultTellTopic for Sarah (which we'll put directly in the sarah object, not one of her ActorStates).
+ DefaultTellTopic, ShuffledEventList
[
'{The sarah/she} listens politely while you rattle on. ',
'<q>How interesting!</q> she declares, <q>You must tell me more some time.</q>',
'<q>Really!</q> she declares, <q>how fascinating!</q>',
'{The sarah/she} does her best to suppress a yawn but can\'t quite
manage it. ',
'{The sarah/she} listens attentively, apparently hanging on your every
word. ',
'<q>Yes, I see,</q> she nods understandingly. ',
'<q>Well, well!</q> she smiles. '
]
;
Of course this will not be entirely player-proof, in that the determined player can generate some fairly bizarre exchanges, such as
>tell sarah about the worst experience you've ever had
"Well, well!" she smiles.
But it will probably do well enough for most game-related exchanges.