Same flight, no issue ever. Girlfriend and I were flying SYD-HKG together, me in W, her in Y and we checked in together in the W line (J line was crazy long and W line was empty, had J line access from OWS). Only comment from the agent was asking me why my GF was in Y

I offered to switch seats with her but she was adamant that I needed the extra space of W much more than she did...