[brudgers]

With the exception of welders, the other trades you mention are all licensed professions. In the case of welders, serious work requires certification and gets inspected to reduce the chance that someone dies.

A runaway online shopping cart can't crush a child. It's more the case of lower standards in software.

[CyberFonic]

But the same lax standards are used by the likes of Toyota when developing software for their ECUs - now that has resulted in crashes and fatalities, see: http://www.edn.com/design/automotive/4423428/Toyota-s-killer...