Conclusion
From the people I've talked to, different agencies and clients have different practices regarding integrated shoots. Some do it frequently; others rarely. However, I don't think there's any question that production budgets are going to get more and more squeezed in the future.
When this happens, it's inevitable that companies and agencies will need to share production assets whenever possible.
If you find yourself working on an integrated shoot, keep in mind the more people you’re working with, the more room there is for confusion and disruption.
Don’t plan on showing up at the shoot and winging it. The more precisely your shots are laid out and prioritized, the more likely you are to have fun on the shoot and end up getting the video assets you need.