Are retals in express improper etiquette? Asking for a friend.

No, hit hard and don't apologise :-)

why should those be?

I got a message in game trying to tell me retals are iffy etiquette in express lol.

I think he's mad after his 2nd LG I turned him into a parking lot. Express is fun

Good LOL

Always retal. 1:1 seems completely fair to me. If the original attacker gets caught doing any spy ops after the retal, it's on.

What kind of spy ops? I like to spy on people to keep an eye on what they're doing.

I always send a cordial message about the retal. If I get even a standard spy op in response to that it's killin time. That spy op tells me you're thinking about trying again.
If i get spy op'd at the end of the set that's fine. I check out other countries too. It's all about the players intentions.

if its 1:1 in hits you need to both be outside GDI to kill him tho.

I think Kill:2 is reasonable. I think its a bit circumstantial tho. If I get hit 2x early by some inactive nub I will let it slide. I rarely ever maim people on this server since there used to be so much DR-abuse going on here. Maybe the grabbing changes actually making maiming viable again, ironically at the same time as BRs and ABs become incredibly circumstantial.

Either way the way I see it is that if my set is ruined I will make sure whoever ruined it get some negative feedback from me, but if my set is not ruined I will likely carry on as best I can.

But honestly I almost expect RoR on this server so I buy up defence after retalling if I can stop it from happening. Saved me plenty of times from having to kill ratski and his cat for instance. :)