It is interesting to hear Mr Tibbetts say perhaps Mollie voluntarily got into a vehicle with someone she knew.
It reminds me of the earliest new articles asking the public in Utah to be on the lookout for her.
"IRON COUNTY, Utah — Police in southern Utah are asking the public to be on the lookout for a missing Iowa woman who they say has family connections in southern Utah."
"The Iron County Sheriff’s Office says they don’t know if Tibbetts is in Utah but they say she has family connections in Southern Utah, and they ask anyone who sees the woman to call their local police agency."
JULY 23, 2018
Police in southern Utah ask residents to be on lookout for missing Iowa woman
This also gives credence to the possibility that it is a voluntary absence. Utah seems random - making me wonder if her online data led there. I hope her dad is correct.