This is a valid concern, but part of an even bigger choking concern. Safety standards for many products that will be left around a house include a test on whether a
three-year-old could take apart something that contained a part easily swallowed. Bingo. That's an e-cig.
How long would it take a child to pull apart some e-cigs? One of mine has a cart that literally falls out if turned upside down! A small, cig-sized e-cig would divide into battery, atomizer and cart. Of the three parts, the cart is the most dangerous to the child, since it contains poisonous nicotine (maybe not enough to kill, but surely cause a trip to the hospital). Some of those carts are pill size.
And some have filler so loose it either falls out or sticks to the atomizer when the cart is pulled out for refilling.
Government agencies will take note of that. It's an unsafe design, which is why I've argued in the past that the only design that will pass childproof muster is the single-unit disposable e-cig, like the Ruyan Jazz.
The carts have always presented a danger to children. If one rolled onto the floor and was encountered by a crawling toddler, what would happen? The first thing a small child does is put something into the mouth. If the filler contains liquid .. big problem. If the movement is unseen by a parent, even bigger problem!
If paramedics respond, how will they know what has happened? Where are warning labels? Where are ingredient lists?
E-cig design has been fatally flawed for a long time, and this has been brought up and discussed before. Manufacturers have taken token steps toward safety, yet dangerous products remain for sale. This thread is relevant, but just the tip of the danger iceberg.