table.table-bordered works fine for viewing, but in printing, only the first and last rows have the thick gray left border. All other rows have a thin left border.
To reproduce, load http://twitter.github.io/bootstrap/base-css.html#tables in Chrome 27.0.1453.94 m, right-click and go to Print... and look at the .table-bordered example on page 13.

Please check whether this (or similar) problem still occurs with v3.0.0-wip.
Just checked v3: Most of the borders look fine now, but the two thick left borders still look like this and there is a glitch at the right corners.
Fixed in v3 with some border-collapse: collapse;. Thanks!
This works for me
.table-bordered th,
.table-bordered td {
border: 1px solid #000 !important;
}
Most helpful comment
This works for me