Can you make a case for this?

Generally speaking, it is my opinion that it is better to not embed the css classes or rules as well as javascript code in the web2py core function because this makes difficult the customization from the user.

A pratical example:
I'm developing a Zurb Foundation (http://foundation.zurb.com/) theme pack for web2py.
Foundation framework has a conflict with SQLTable due to the "even" css class.
/* from zurb foundation core file */
table tr.even, table tr.alt, table tr:nth-of-type(even) {background: #f9f9f9;}

Zurb foundation counts the table rows starting from header so the row will be even for web2py and it will be odd for ZF: we will have all the rows coloured with #f9f9f9
Currently, to solve the issue I could override the above css rule in my custom css file but in such case I should check if the modification will be compatible with the future ZF releases.
I could, in alternative, manually remove the class with e.g.:

zf5_table = SQLTABLE(records)
trs = zf5_table.elements('tr')
for tr in trs:
    tr.remove_class('even')

Or by using jQuery.

But would not it be easier to write:

zf5_table = SQLTABLE(records, even_row_cls="")

?

Moreover I don't think that my pull request infringes the web2py backward compatibility.
Thank you for your consideration.