Do you acknowledge people arriving when you have started the presentation?

Years ago I used to get upset with people who arrived late because I assumed that they could not be bothered being on time.  I am slightly embarassed to admit that I would ignore the late person, sometime even glaring at them or completely ignoring them.  I found it even more annoying that they would distract everyone else in the room by wanting to provide a detailed excuse for being late.  Generally, this would erode my ability to connect with the audience and be a source of distraction in my presentations.  Interestingly, since I have had kids I understand that things come up that can be beyond the control of the attendee (and it is not always about me!).  I now realise that when people are late, it may be that they really wanted to be there on time and feel awful for interrupting and perhaps disappointed that they might have missed some of the important information in the presentation.  Now I always acknowledge people who arrive late, and take time to reassure them that it is fine with me and they can settle in and enjoy themselves.  I might take the opportunity to recap a couple of the main points covered so far for the benefit of the other attendees or set up a paired discussion and take some time to go and speak to the person who has arrived late to settle them in.  I remind myself that the person arriving late may be dashing from their leadership role because they would rather squeeze my presentation than miss out on the incredible wisdom and insightful pearls of wisdom that I am so generously dispensing! (ahem).