Is it possible for a cannula used during lipo to puncture a silicone breast implant causing a leak during liposuction?

Dear Ms. Veronicavee,
Thank you for your question. You bring up a very important topic: Complications
In any endeavor in there are inherent risks that are usually and significantly out weighed by the benefits.
Example: when we decide to drive our car, we fasten the safety belts, trust the air bags are functional and that our automobile is well maintained with tires that have adequate tread and functioning brakes. Your drivers license is up to date and your insurance policy is in effect.  Despite all these precautions accidents can still occur.
Thus likewise a certified operating room is full of very sophisticated equipment and highly regulated in a accredited surgical center.  Your chosen Plastic Surgeon has received his training and is Board Certified. However like driving a car inadvertent actions can  result in unintended consequences. 
General risks of any procedure fall into several main categories categories and need to be discussed before surgery:
Bleeding
Infection
Anesthesia
Inherent risks to that specific procedure 
Your question focuses on inherent risks. So, answering your specific question is: yes a liposuction canullae has a low potential of penetrating a breast Implant. However this would be considered a very rare outcome after liposuction. 
This brings up another issue: the experience of the car driver or the Plastic Surgeon. I am reminded of old adage: “it’s not the club is the golfer”. 
I trust your chosen Plastic Surgeons is a experienced and Certified by the American Board of Plastic and ideally a member of the American Society for Aesthetic Plastic Surgery (denoting by membership as having met additional criteria and a focus on Cosmetic Plastic Surgery).
My best wishes and a successful safe surgery,
R. A. Hardesty, MD, FACS
Diplomate and Certified by the Am. Bd. of Plastic Surgery
wwwimagineplasticsurgery.com
Awardee: RealSelf Top 100
4646 Brockton Ave
Riverside, Ca 92506
(951) 686-7600

Yes, if the cannula comes into contact with the implants, then the implants can be damaged.  This is why preop markings and careful intraoperative positioning is so important.Best wishes