One time on a transfer, I was given my desk, a phone, a laptop, and a list of training courses I'd need to complete. No one asked me to lunch, only a few people came by to say hello. It was fairly isolating. You tend to remember these experiences for a long time.
One risk is that new hires will jump to wrong conclusions about the organization. With new executives, the risk is that the organization will jump to the wrong conclusion about the new executives themselves.
Properly training new employees so that they are ready for their first day of work is crucial to ensure they feel welcomed and prepared to contribute from the start.