I've spotted competition twice. The first was at a gas station I used to get assigned by default at a prenegotiated bonus. That prenegotiated arrangement had ended, and I had noticed all of those brands had been taken by someone else before bonuses were offered. I approached her thinking I might get some insight into how she outnegotiated me. Without going into too many details, it turns out she was down on her luck living out of her vehicle going town to town doing shops at base pay. She complained she was not even paying for gas most days. I wished her well and the next round those shops stayed on the board. (I mentioned this forum, but she was not aware of it, just for those wondering.)
The second time was at a gas station where I was doing the regular audit with a hefty bonus. That was when they had a separate signage audits on one of the apps, requiring lots of measurements and such. I had noticed it was taken that morning at about a third of what I was getting. I arrived and saw someone already doing the audit, running back and forth taking the photos. I did my shop and left while she was still going back and forth. I said hi, but she didn't seem to want to talk.