If you were to hire two private investigators to follow each other, it would create a unique and potentially amusing situation known as a "mutual tail" or "double tail." While this scenario may seem unusual, it has been known to occur in the world of private investigation. Here's what might happen:

1. Initial suspicion: When both investigators realize they are being followed, they would likely become suspicious of each other's motives. They might wonder if their cover has been blown or if they are being targeted by a rival agency or client. This suspicion could lead to increased caution and paranoia.

2. Counter-surveillance techniques: Both investigators would employ various counter-surveillance techniques to identify and evade their pursuer. These techniques could include changing routes, using disguises, employing decoys, or even attempting to lose the tail in crowded areas. Each investigator would try to outsmart the other, resulting in a cat-and-mouse game.

3. Surveillance errors: The pressure of being followed by another skilled investigator might cause mistakes or lapses in surveillance techniques. Both investigators might become overly cautious, leading to missed opportunities or compromised surveillance footage. This could result in a lack of substantial evidence or incomplete reports for their respective clients.

4. Communication breakdown: In some cases, the investigators might attempt to communicate with each other to clarify the situation or negotiate a truce. However, due to the nature of their work, they might not trust each other's intentions and may avoid direct contact. This lack of communication could further complicate the situation and prolong the mutual tail.

5. Client dissatisfaction: Ultimately, the clients who hired these investigators may become frustrated with the lack of progress or inconclusive results. They might question the competence of the investigators or the value of their services. As a result, the reputation of both investigators and their agencies could be at stake.

It's worth noting that the scenario described above is hypothetical and based on the dynamics commonly associated with private investigations. While there are no specific examples or references to point to, cases involving mutual tails have been reported anecdotally within the private investigation community. However, due to the confidential nature of their work, such incidents are not widely publicized.

In conclusion, hiring two private investigators to follow each other would likely result in a convoluted and challenging situation. It would create suspicion, counter-surveillance techniques, potential errors, and communication breakdowns. Ultimately, the clients' objectives may not be achieved, and the reputation of the investigators involved could be at risk.