A lot of companies schedule interviews with a natural break in the process partway through -- basically you do phone screens, with people not progressing beyond those, and the in-person interview can be split to morning, lunch, after-lunch; senior people (or larger groups, or people with more constrained schedules, ...) meet with candidates after lunch, and if someone is a no-hire based on the morning, the candidate doesn't know about the afternoon phase and is told he can go home before or after lunch.

Personally I think it's important to sell no-hire candidates on the company, since even no-hires might be hires in the future (for different roles, or if they add skills), or might be referrers of other, better candidates, or might end up working for a vendor or customer, or just might make negative social media postings about you which dissuade other candidates. So doing morning interviews, lunch (which turns into "selling the company's mission to the candidate", ideally by a senior person who isn't overly busy, not a random HR drone), etc. for the no-hires.