Why worry? As matter of fact, it is much harder to hack these stand alone Videophone than Webcam. But 100% impossible? No. Secondly, there are thousands of thousands Videophone out in use right now, so if one hacker wants to peeping tom in conversation, it is going to be harder to find which is which but it is still possible, and there will be only few out of thousands. Remember, IP address always changes. So, my answer to your question whether to worry or not, the answer is not to worry about it. You will be ok.
Its too bad some people think that I think too much of negatives. I'm just encourage to be more vigilant, than just to depend on top of line technology and think nothing won't happen. If they still think I think too much of negative, its their problem not mine. Because I am out there warning those who have no clue what technology can do and can't do. Also, I'm sick and tired of hearing those people who said, it never happened in the past so won't happen anyway. Perhaps they look me differently and think differently than what I really think.
What I am saying is that if you want webcam to monitor your baby, great! But if you live in apartment complex, get wired version webcam that just connect to TV, no connection to Internet, than buy fancy one that can be picked up by somebody 1/4 miles away, or even worse anyone in the world can find it, on other hand if you live on mountain in middle of nowhere, then it would be almost impossible for hacker to be able to pick up if it was not connected to the Internet.
My son complaining that couldn't pick up wireless connection when he was with me in backyard. My response was, our WiFi stays inside our house, and I don't want neighbor to snoop in and steal our service. He was like oh makes sense.
And yes, I admit that I have witness some of them who did hack somebody's else conversation back then when security was lax, and there was no real 10 digit local number. As soon as it was being fixed, I knew that it is going to happen but said nothing until it became more secured, and I got complaints from some of hackers that I know of and I gave back "Shurgs" and asked them what kind of business are they into? Where's respect? All of them shut their mouth up. Yes, I was pissed off when I seen them doing such, and had to report and push to increase security on VP, and finally its done. So the VP security had improved significantly.