Good point, I did not think about this.
After inspecting the DOM, there is a specific id for the input field to the Tag Path section named ia_powerChartComponent__settings__addEditPen__dataSource.
I can implement a style rule for this id and set display: none, and have the section be “hidden”…
However, a client could easily remove or modify this style rule and gain access to this field. This is not ideal. The ideal situation would be to have the perspective component driving the DOM not include it at all, and not support any modifications to the source tag path for a pen once included in a chart.
Thanks again for your suggestion.