I look at the attack analysis, which shows me which attackers try to exploit my vulnerabilities. I can check the ticket to see if it's blocked or whether it's a false positive. Whatever the case, if it already exists, I will block it. McAfee IPS has a benign engine, so this may not be a target in your environment. If you just prevent attackers from using it, they will try another vulnerability.
I have physical routers, but they try to make some novel vulnerabilities. This is not applicable to my environment, so when I see this alert I know it's a false positive not related to my environment. In some cases, I change the action of these alerts or attacks to block. This is what happened in one of the use cases I take advantage of from IPS. I got an alert about some attacks in my environment, regarding the SPAN port and server traffic. I saw it and I detected the source point of this attack.