I guess you are referring to the Update button in the viewHtml dialog. All tables added there will be populated with the k-table class. This is by design and what you should do to control the way how table.l-table
elements are decorated is by implementing your own CSS rules in an external stylesheet added to the editor's content area
If, however, you feel that you should have control whether the k-table class to be utilized or not you can post your feedback in our UserVoice portal—http://kendoui-feedback.telerik.com/forums/127393-kendo-ui-feedback
. That way your suggestion will be evaluated by the Kendo community and the Kendo dev team.
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items