I don't know. When I cut and paste, it pastes fine into the post... including formatting and tables!
| Spreadsheet Table |
| Item 1 |
10 |
| Item 2 |
20 |
| Item 3 |
30 |
This was pasted directly from a spreadsheet program into the post reply box.
I used colored backgrounds and a border to make it more obvious. If you had a white background and no borders, the table would still be there, just you wouldn't see the borders.
No mod is required. You must be using a browser that supports the WYSIWYG editor though and have it turned on.