On Pohorje both cross-country tracks and ski slopes are usually part of ski areas.
And as far as I checked myself, you mustn't walk on these tracks.
It is true that it must be marked
and a general warning sign (usually near the cash desk) is not enough.
Last year some track inspector or whatever he was rudely insulted me on one such track at Areh, though I walked completely aside, and also on the part where there is also the usual marked mountain path. I don't know who I was endangering there. The biggest sadness was that two hours earlier the Stolp chairlift collapsed with gross and direct endangerment of lives. (Sadly I didn't know that when the guy attacked me.)
But on Maribor Pohorje you can ride sleds, snow bobs (pležuh) on the ski slope if you pay for the ticket
. I wouldn't know if I hadn't seen it very well with my own eyes on night skiing. If I had paid for the ticket I could surely walk on foot too
.
I mostly ski in Austria and haven't seen anyone chasing anyone off the slope if they know how to walk on the edge and not obstruct others.
But anyway, if there is a warning sign that walking is prohibited, so it is.