If a bad character (e.g. double quote character) is entered in an agent configuration value, it is happily accepted by TSPS infrastructure policy.
The problem is once this policy is enabled, then it can prevent all policies from getting applied to the Patrol Agents (which share the Agent Selection Criteria).
You will see an error under Managed Devices stating "The following policies could not be applied"
The idea is to have a warning when attempting to add a bad character at the time that you try to save the Agent Configuration Variable.
As it stands, TSPS will not give you any indication that there is a problem until you go looking for the applied policy status. Even then, there is no notification given that a particular policy has the poison character, so - at best - the user would need to hunt down the offending policy. At worst, the user would need to contact Support. And nobody wants to do that.
Can confirm: I am Support