Is there evidence to support empiric atrial flutter ablation for patients undergoing PVI for atrial fibrillation in the absence of clinical evidence of atrial flutter? 

Presumably, triggers for typical atrial flutter, emerge from the left atrium. No randomized trial has shown the combined ablation is more sensible than performing one sided atrial ablation without evidence of typical right atrial flutter.

Yes, there is some evidence of doing an empiric CTI line during PVI for atrial fibrillation in the absence of clinical evidence of atrial flutter.

The best summary of data is a meta-analysis joint project between Montefiore and Texas Arrhythmia Institute and Dr Lakkireddy from 2020 JCVEP (Romero et al., PMID 32530541). The long and short is that the CTI line didn't help (and almost a trend toward more atrial arrhythmias) when looking at AF without AFL. They also looked at AF + AFL and a CTI and you won't like what the meta-analysis showed... again, no benefit in reducing future atrial arrhythmias. Perhaps the cat is already out of the bag with atrial myopathy, changes at the cellular level, fibrosis such that stopping organized flutter with ...