Can Las Vegas slot machines be trusted? The state of Nevada seems to want the answer to be yes. So it demands access to all software, and reserves the right to do unannounced spot checks on the hardware.
Now, what about electronic voting machines? The US government seems to have a more relaxed attitude to them than NV does to the slots. When it comes to voting machines, the software is secret, and the hardware is not subject to inspection.
The source for these and other disturbing comparisons is Steve Freeman, an academic, via The Washington Post and Reddit. The article is from 2006, but I don’t think much has changed since then. I am among those who thinks that voting software should be free/open source, or at least available for public inspection and running on machines subject to independent checks.