In fairness it's very hard to force someone to undergo a medical procedure (and doing so potentially brings a whole host of other issues), as much as it may have seemed to make sense in the circumstances.
It has also been made clear that other health checks do take place daily on those workers in the MIQ facilities, and that Covid swabs are a second line of defense.
If you dont want to undergo a swab then ask to be relocated to a different site, away from the area of risk (no different than hospitals during March/April, or those essential workers (eg supermarkets) who felt the personal risk during L4 and L3 was too high.
Sports players in Australia, Europe and the US have accepted regular testing as part of training and playing. Wouldnt you want to know that you're in a safe environment as evidenced by regular testing?
What other checks take place? A series of questions that may or may not be appropriate? I believe that the absconders from the Novotel Ellerslie that couldnt find their way to Wellington were asked "Are you or have you been feeling unwell?". If thats the extent of checks then that'd be extraordinary but, once again, unsurprising.