attack

If you can see the enemy defense and prepare an attack, is the attack button deactivated? Or can you click the button and no attack gets triggered.

Which Veteran World are we talking about? Veteran 6?
When w3as you last manual login?

Are you playing as a sub? Subs cannot attack in PvP on any world.

I am in World 60, and not playing sub. Just my own account. Last manual login about 2 weeks ago. But my question is about attacking own alliance member's base for removal from spot. I somehow recall that it was possible by pressing some combination of buttons (like shift+alt+left mouse)

Players cannot attack members of their own alliance, members of alliances set to 'ally' by and officer or members of an alliance set to to 'NAP'. Red coloured and white coloured alliances and players as well as the forgotten are the only ones you're able to attack. I've played for 5 years and in that time it has never been possible to attack your own alliance members.

If a player won't move, for example because they haven't logged in for a long time, then it is up to an officer to remove them from the alliance.

The ability to attack your own alliance members was removed about 7 years ago. This illegal exploit was abused heavily. Anyone not cooperating with alliance leadership should be removed from the alliance.