Wouldn't they be capable of getting nanobots into our bodies regardless?
Discussion
Of course the could. But there is a red line for them too. As they and all other species in the universe have to follow the rule of free will they can't do it without your permission. And your signature on the contract will give them the allowness.
The signature is more important than anybody can even imagine. Take care what you sign and even how you sign and with whom you do a contract.