Hello my friend.
There are a few layers to answer your questions, but TLDR: it affects player deaths (compensation, no loss or regular death), but you are not kicked from the game in result of this system (you can get kicked because of the attack) and you won't get any kind of notification about it, but you can check your character in your account page to see if your death was compensated or not.
First, Tibian servers are hosted behind services that provide anti-DDoS protection, which will severely attenuate the results of such attack on players.
Second, whenever a DDoS attack is undergoing and the first layer is not enough, causing connection and ping issues to players, any casualty (pvp or pve deaths) are instantly refunded. There is no server save needed or anything like that. If a attack is detected, this protection is automatically activated.
Third, sometimes, when a very unusual event happens with massive casualties to players (like a stack of 100 players getting hit by Gaz'Haragoths doom) there is a chance that the same protection from layer two is applied, even tho there is no DDoS attack detected at the moment. This is kinda like a fail safe for unexpected bad experience caused by unknown reasons. It is extremely rare (I saw it happen only once), but it exists.
You can check "types of death" in Tibia's website, while editing any character of yours.