What happens if you block a user and then you play in the same tournament?

Do I go for d4 Nf6 c4 resigns?

You will have to play that game.
Blocking someone does not prevent the pairing in arena-tournament, for obvious reasons.

From https://lichess.org/terms-of-service - please scroll to Fair Play Violations.
Sandbagging - This is where a rating is artificially deflated, such as by resigning early, losing or drawing having put no real effort into the game...

Ok. Thank you.

@Funkmaus

Of course I understand that in Arena and Swiss tournaments you have to compete against everyone who is drawn.

But you can't call it Sandbagging if @Mr_Kuryakin is totally unwilling to play against someone he has blocked for important reasons! He takes that one loss and gets some satisfaction from it - but it's not rating manipulation that needs to be sanctioned.

Indeed, I believe that one reserves every right to resign in any game they don't want to play, for whatever reason, maybe even due to an irl emergency. As long as it is not a repeated violation, I don't expect it to withhold any consequences for their account. Cheers!

Dear @Tenakel,
thank you much the ping and for questioning what I have wrote in #2.
To avoid misunderstandings, I will answer that in detail giving some insights in how our boosting/sandbagging detection works.
First of all, as you see, I have enabled the mod-eye over my post – just because all I did is simply officially explained the ToS.

Agreed, you got a point – if Mr_Kuryakin (or someone else) is totally unwilling to play against that ONE person they have blocked and it will stay by ONLY that ONE loss, then it is not rating manipulation, that has to be sanctioned.

But, most of our users play here on daily basis, to the same times and are not participating in just that ONE tournament.
If someone is playing on same daytime and has same time control preferences as the person they have blocked, the chances that they will get paired again are pretty big.
So, what now? Will they be willing to play them again?
I guess we can suppose, that there will be ANOTHER game they have thrown to the person they have blocked by resigning early...

In addition, people mostly do not block just ONE person – as you say, for important reasons.
As an active arena/swiss tournaments player it is very likely that they will be frequently facing people they have blocked (or people they are unwilling to play for other reasons).
Please understand, that if such games are summing up and resigning early becomes a pattern the user might get a warning first or even get marked.
(Blocking does not apply for tournament pairings, if that would, then one could just block all top-players to avoid the pairings and win the event xD)

All games we play are public information and are viewable via advanced search. Setting some filters will show us the games in question; besides, we have an automatic system running over all tournament/pool games which detects possible rating manipulation and generates reports.

There were users who tried to “outsmart” the system by failing to make first move against specific people in tournaments instead of actively resigning early. Here, we can only suppose that it was the case because they have blocked them, they might have had other reasons.
But, over time, it became a pattern – we could clearly see over advanced search that they were not making first move against SAME specific people SEVERAL times.

Let me bring the simpliest example on how rating manipulation (sandbagging) via advanced search can be detected:
https://lichess.org/@/ZerkingQueen/search?turnsMax=5&perf=1&players.a=zerkingqueen&players.loser=zerkingqueen&sort.field=d&sort.order=desc
As you see, there are only 8 games that I have lost under 5 moves over 10k games.
Those were due to being lefonged or because my connection dropped the moment the game started.
The latter is very painful especially as white - because those are the cases where I also "forgot" to berserk.

Hope that explains. Wishing you and others who read this happy chessing and all best :-)

Hello @Funkmaus ,

thank you very much for taking the time for your detailed explanations and for the interesting insights into how lichess works in the background.

I absolutely agree with you, although the following test passage in particular convinced me:
"Blocking does not apply for tournament pairings, if that would, then one could just block all top-players to avoid the pairings and win the event xD"

Thx for your work here in the forum.

I wish you all the best too, bye.

If I could block someone to prevent being paired against someone then I could just block the champion, or many champions in a tournament, to try to get more favourable games.

@Mr_Kuryakin said in #1:

Do I go for d4 Nf6 c4 resigns?
Are you Magnus?