Blackbaud decided to remove the error limiting the functionality of the webview GDS reports a week after I posted this idea. Thanks!

https://community.blackbaud.com/blogs/13/10148

In webview, there is a requirement that standard reports have columns populated with gift types, even if the column is not included in the output report. This is different than in database view, where it lets you run the report without populating some columns with gift types. In both database view and webview, gifts from all columns, whether or not they are included in the output report, are included in the report grand total, so you can run the risk of invisible columns adding to the grand total. In database view, you can workaround this by removing all gift types from absent columns. But in webview, you cannot, because an error message keeps you from running the report. This means that in webview, if you populate the absent columns with gift types to make the error messages go away, the report runs the risk of counting monies in the grand total of the report that shouldn't be there.

Either the error message needs to be removed from webview so that the same workaround that worked in database view can be used, or the issue of the report grand total including values from columns that are not selected in the report should be fixed, so that the workaround in both places is not necessary.

I brought this issue to support and they said it was an issue for the ideas forum. Seems more like an error in functionality, one way or the other, but oh well. My specific issue was with Gift Detail and Summary Reports, but I imagine that it may apply to other webview standard reports as well.