We are running a cocktail reception at a local establishment for a woman is retiring from our company after 34 years of service. Emails were sent, clearly stating RSVP, with the additional notation that we really needed a head count by a certain date. It's 4 days past that date & we have yet to hear form roughly half of those to whom an email was sent. A follow up email was sent 5 days ago. Many of those who have yet to respond are executives or those in upper management. I am stunned that there is so little regard for what I consider to be a basic social practice. Just as an FYI, I would be considered to be in mid-upper management, so it's not like they are brushing the invite off as coming from "a peon" (before your get your knickers in a knot, I'm saying that sarcastically).
Second situation. My daughter & SIL are having their first big party in their new house. They are in their late 20's & this is a very big deal for them. Again, they used e-vites. My sister has 2 kids in their mid 20's, both in professional jobs. DD sent invites to them. Standard RSVP. She has heard nothing. On cousin was the Maid of Honor at her wedding. I made a remark to my sister & her reply way: Boy, did you get up on the wrong side of the bed this morning".