Committed fix to 3.3 EE maintenance branch at revision 40944.
This issue could be reproduced with the IF 3.0 release, and perhaps it started long before that.
It seems that the original intention of the developer(s) of ice:dataTable was to implement a simple approach to align the columns of the various table elements that compose the component, by giving the columns equal width when scrollable=true, since all column cells are given the styling "width:100%;overflow:hidden;" to simply hide the contents of the cell if its contents could increase the width of the column. However, setting width:100% to all cells does not accomplish this. It is necessary to set table-layout:fixed; on the three tables (header, body and footer). This was done, as well as adding overflow-y:scroll, so that the scrollbar always appears (when scrollable=true) and have more consistent widths. Also, the spacer element in the header that accounts for the scrollbar width was tweaked to adjust to these changes, and another spacer element was added to the footer.
Unlike, ace:dataTable, there just isn't an advanced script that calculates the column widths of the different table elements in a table component, and ice:dataTable simply doesn't have an extended and robust client side codebase as to set more precise column widths and alignments, as we do with ace:dataTable.
Attaching screen shot for Chrome30.