Currently there is no way you can hide/remove RESET button.
I think end users need to be educated about the benefits of having that button out there. During Planning end users can make tons of selections in those context selectors and if they wish to fall back to the original selection that was on the page they can use that button. It is exclusively for the SELECTION and not for the data. Remember Change management is an art
RESET appears when a user made a specific selection on a page, and data that corresponds to that selection is shown on the page. Clicking on Reset, the page is set to its default view.
Example: Let's say by default, Rep-1 data is shown on the page. It means whenever the page is opened, the data corresponding to Rep-1 is shown. If a user changed the selection to Rep-2, now a RESET button appears indicating some change in selection had happened.
There is no way to remove the RESET button to my knowledge, however you may educate the user about its functionality.
Thanks for your update. Need clarity on this scenario, if we create a page with multiple CARDs then which filter corresponds to the default view (more than 1 Card is built in a page). For an instance, i have a page which displays plant sales data from 3 regions (say India, China & Singapore) and restricted by access. When a user logins to a page, selects India / Plant1 from home page and navigates to 2nd page, which displays data for Plant1 in India (as per selection), but if the user clicks on RESET button, the page switch to India / plant2 (plant2 is not associated with India) displays some other plant for India, obviously a wrong information.
Note: There is no parent child relationship for Region and plant