What's good for the goose...

"During your deliberations in this case, you must not consider, discuss or relate any matters not in evidence before you. You should not consider or mention any personal knowledge or information you may have about any fact or person connected with this case that is not shown by the evidence." -- Instruction given to juries in Harris County

If the jury as the trier of fact cannot take into consideration any personal knowledge they may have that was not put into evidence, then I am hard-pressed to see how a judge sitting as the trier of fact is permitted to do any differently. In Texas, at least, Judge Donald Armstrong's ruling in the Howlett case (discussed earlier today) would be an abuse of discretion.