Funny enough in my time in Wizzair I was never called on my days off. I might have seen maybe couple of missed calls from ops, but I am notoriously slow to answer the phone. I know in Romania it was a different story.
To be fair I was called 2 times only from standbies in 2 years, while in my current employer I get called 50% of the times, despite running a slightly higher crew ratio. Never understood why.