Is it normal that I can now see the renters worker name and ip of his pool?
I used to be only able to see rigname.lease or something.

I can also see all his/her backup pools AND worst thing is. I can remove them. They are in my pool list as usual pools. I find that odd. When cgminer is restarted it also doesn't necessarily take the renters pool if I myself have pools in that list (obviously those would be at the bottom and only work if all pools of renter are dead).

I feel it's strange that the one who is renting his rig can check or at least remove the pools of the customer. Obviously the owner of the rig could just change his cgminer settings if he has bad intentions, but enabling it on the website is just another option to make mistakes.

I do agree that there should be a way to check if the customer's pools are actually alive or that indeed the rig is mining for the customer as should be.