This is how I imagine it to work, too.
Because now I can’t get on vacation anywhere, because I have a couple no-vacation tournaments.
So, I’m “not allowed” to use vacation in tournaments that allow it, because everything is under the same system. Also, sometimes I go on vacation when I have a feeling my opponent is going to time out but they are usually not neglectful, so maybe something happened in their life. I would turn on my vacation, hurt nobody, and keep that game going until my opponent comes back.
Also, another reason to not automatically DQ is there are always new players, and also new rounds. I’m someone who very much likes no-vacation tournaments, but on the other hand sometimes people forget, or are new and don’t know. Or there was time between rounds and they turned on vacation thinking they will be on again before next round. This is usually solved with a DM and they turn vacation off again. It would be unfair to just DQ them if the solution can be “use vacation as you like in all other parts of OGS (so just a click on the cockpit for the player as they wish), our specific games will keep running as per tournament settings (a click for the TD and settings as agreed for everyone)”.