The concern would not to be labelled a scab.
What is the definition.
If there was no strike, and certain guys wanted to top up their bank accounts with some casual/partime work for a few months, is there anything wrong with that.
Exactly what QF engineers do on their holidays, pushing fulltime contractors out of work, lowering their TnC's and chances of training.
Bit like training your dog to s#)t on next door's garden.