That will still work, but your CSS will likely need to be more specific to override the default styling. The below will work without overriding the hover styling.
Code:
.cb_template .cbUserListDiv.cbUserListLayoutList > .cbUserListRow.sectiontableentry1:not(:hover) {
background-color: grey !important;
}
If you want it to override hover styling as well then remove :not(:hover) from the CSS.