Omega Leader: Enemy ships that you have locked cannot modify any dice when attacking you or defending against your attacks.

4-Lom: When attacking, during the "Modify Attack Dice" step, you may receive 1 ion token to choose 1 of the defender's focus or evade tokens. That token cannot be spent during this attack.

If I'm attacking OL, I'd argue that I am not modifying dice but merely preventing you from modifying dice. Has anyone come across this before?

Yes, totally works. If you can't modify, then it will help you punch a damage through if you prevent him from modifying as well.

Seems legit to me. You arent touching the dice....technically...preventing modifies isnt modifying.

I was actually playing OL in a tournament on Saturday and this came up. I agreed with my opponent that it should work, but he wanted to check with the TO anyways. He came to the same conclusion that this thread did.

X-Wing rules define precisely what modifying a dice is: you can add a die result, change a die result or reroll a die. 4-LOM's ability does not do any of these things. It just happen to trigger in the modify attack roll step.

as above

adding results (evade)

changing results (focus)

and re-rolling dice (TL)

are defined as "modifying dice"

anything else (adding actual dice not dice results-Zeta Leader, removing actual dice not dice results-Kanan, canceling results ala crackshot etc.) are fair game

4lom doesn't even touch dice, he just prevents the use of a token