While Social Pinpoint does have a solution in place to deter stakeholders from voting multiple times on the same comment, there is the possibility that a stakeholder may be able to vote more than once.
Likes and Dislikes, or up/down votes, DO NOT use IP addresses to identify the user. Instead, Social Pinpoint uses the local storage of the user (i.e. the memory of the user's browser) to track whether or not they have left a like/dislike on a particular comment on a project. This utilization of local storage will deter the user from voting again more often than not.
If a stakeholder submits multiple votes, regardless if they are making the effort to spam a comment, they are doing so quicker than the local storage is updated. Local storage can present other related issues, such as the user being able to clear out local storage, which would allow them to vote on the comment again. Or, if the user changes browsers or is in incognito mode, then they will also be able to like/dislike a comment twice.
While other solutions are available, all present similar spam risks to using local storage as described above. Unless a platform requires users sign in to engage, which Social Pinpoint does not, there cannot be 100% accuracy in determining who has voted for what regarding comment votes.