[@Jangel13] It's not often Tsukiko actually does invite someone to walk with her. To be honest, it never has happened and the only reason she had Hayato sit near her is she wanted to gauge Hayato and her brother's relationship. He'd be a fool to turn it down, but he doesn't have to accept he doesn't want to. It may be a once in a lifetime opportunity to get closer to her and improve his status with her. Most boys would kill to get an offer like that, because one she doesn't like boys and two she doesn't like walking with people she doesn't know though she does make exceptions based on the conditions they made with her. 

So what is he going to do? Accept her invitation or decline it?