Depends on the individual company policy. Before I started staying home, my company held an annual weekend conference for all employees and their families at a resort area. Purchasing these tickets for employees and families wouldn't have been unexpected for my company ...
At the end of the year, they did "charge" us for family members (a small fee that they charged because of IRS regulations, but significantly less than what the weekend truly cost). I have been gone now for nearly 3.5 years, but am still a stockholder. I was included in a couple of conferences after I left, as was my family.
So, while I believe what my company does is rare these days, it's not unheard of .... Why do you ask?