You miss the point. They are not actually sick. They ring in sick rather than 'work to rule' or go on strike so they still get paid.
I know they're not but remember Southern don't even employ enough drivers to run the service without over time normally so they sure as heck haven't employed enough drivers to cover normal sickness. The fact that the union members phone in sick falsely obviously doesn't help the situation. Personally I'd get the government ministers, Southern execs, Union officals and striking drivers into one massive locked barn. Strip them. cover them in honey and let millions of wasps loose into the barn. Don't unlock the barn until they all agree a way forwards - after all it's effectively what all the CJTCs have done to their customers.