That's not a big deal at all. They do sometimes have CMs that only allow seating for those with food from that establishment, but that would only happen when it is very busy (do note that DB7 can be hard to find a seat sometimes, though there are some outside too). As long as part of your party is getting food from there it would be absolutely fine. Chances are they won't be enforcing that anyway, but it can happen (I don't know that they ever do it at DB7, but I have seen it at other QS places like Satu'li, though they only restrict that for indoor seating there).