User blog comment:IamJakuhoRaikoben/Chapter 474: In the Moment of Complete Silence, Review./@comment-23853100-20160223120945/@comment-7418318-20160223150824

That train has already passed. If they could just teleport into the guild at will why would they have not done it before and suddenly do it now?

Acnologia won't go to the guild, since he's after the Dragon Slayers and currently there is no Dragon Slayer in the guild and Acno knows that.

Lucy, like all the others, have to rest at some point. They can't stay awake 24/7 or they won't be able to fight if/when the enemy attacks the guild. Right now everyone else is awake (save for Natsu), which makes it a very good time to rest.

Also you ignored my question: What do you expect her to do? Or rather what can she do in this situation that all the other people present aren't already doing right now?

And why complain only about her? The others are only staring at the radar too, which would mean if someone wanted to sneak in, they would have an easy time to get past them.