Classified Point Cloud data are increasingly the form of geospatial data that are used in engineering applications, smart digital twins and geospatial data infrastructure around the globe. Characterized by high positional accuracy such dense 3D datasets are often rated very highly for accuracy and reliability. However such data pose important challenges in semantic segmentation, especially in the context of Machine Learning(ML) techniques and the training data employed to provide classification codes to every point in massive point cloud datasets. These challenges are particularly significant since ML based processing of data is almost unavoidable due to the massive nature of the data that. We review different sources of uncertainty introduced by ML based classification and segmentation and outline concepts of uncertainty that is inherent in such automatically processed data. We also provide a theoretical framework for quantification of such uncertainty and argue that the standards of accuracy of such data should account for errors and omissions during auto segmentation and classification in addition to positional accuracy measures. Interestingly, the ability to quantify accuracies of ML based automation for processing such data is limited by the volume and velocity of such data.