Sometimes, a short-term rental doesn’t live up to its billing. Here’s how to recognize red flags before you turn up at the front door. (Weston Wei/The New York Times) By ADRIENNE WICHARD-EDDS When my husband and I followed our GPS to the charming Maine saltbox home we’d rented on Airbnb in July, we blew right past. We circled back, finally accepting that we’d arrived. Surely, this sad shack on top of a retaining wall at the back of an empty lot was not where we’d planned to spend our summer...