To be fair the Limit is posted as the limit. If it is not safe to do so you don't do the limit (or if you don't feel comfortable with the limit for some reason). If it's 110km/h you won't be doing 110km/h if it is pissing down with rain. If you are towing a caravan doing 110km/h isn't ideal..... Not to mention slower speeds, you have more time to react and fix if something does go wrong. So the term going under the speed is "safe" isn't correct that is true, but it effectively does lower the risk of something happening.
TBH accelerating up to the speed limit, if you get no wheel spin is 100% legal. A cop could try to get you for reckless driving but goodluck with that.
There is a reason speed limits are posted. Have you ever seen what happens to a car when a red kangaroo hits it at over 100km/h? Or you blow a tyre? Or the tests showing you the difference in speed makes to stopping difference. So like i said. There is a reason for the speed limits they have set.
Now in saying that...
Those limits were decided many a time ago, cars are much safer now. They come from back in the day when there was no seatbelts. So are they outdated? Yes they are.
I do think our speed limits need looking at. IMO all 110km/h "freeways" there is no reason for them not to be 130km/h. There are many studies on this.
Also im one of the younger ones. 24.