Why do we think this tweet is a payback for free stay?

Because that is the history of Tori & Dean the grifters and fakers...

Tori Spelling thanks San Diego Zoo for freebies and comps for family

We'll help you de-code this Tori Spelling tweet! 
"I promised you if you comped us for the day, admission, food, toys, shirts, I'd plug your zoo on my twitter!"