The Seller Won't Meet in a Safe, Public Place
A legitimate seller has no problem meeting somewhere safe, visible, and convenient — a busy parking lot, a bank, or a police station parking lot when appropriate. If a seller insists on meeting at an odd location, pressures you to come to a private residence late at night, or keeps changing the meetup spot, treat it as a warning.
Houston police recommend safer, public transaction locations, and some Houston-area agencies and campuses provide designated safe-trade locations. A seller who resists a reasonable public meetup is telling you something.