I have often just booking 5x 1 night stays for the 5000 point bonus. Sometimes the reception staff are helpful with this and all I need to do is each day re-activate my room card. At the end I then get 5 bills.
Some hotels have then modified my reservation and removed all bonus points...what I did in these cases was contact IHG customer service and they gave me the correct points.
It may be in the T&C but in my experience it is never enforced!
Try it...but it is some hassle for longer stays. I have a 10 night stay coming up and I couldn't be arsed with 10 individual nights.