I’ve gone back in time to v7.9.9 and can’t remember the recommended way to use expression tags. I know these are supposed to use a different scan class, but is that all? I was just going to use leased.
You might be thinking of DB/Query tags. I don’t think there’s anything you need to watch out for with Expression tags unless they are abusing the runScript function.
Ok cool 
cheers
No runScript abuse is happening