diff --git a/lstchain/scripts/lstchain_r0_to_r0g.py b/lstchain/scripts/lstchain_r0_to_r0g.py
index 212a16c5e8..c4dc721fa3 100644
--- a/lstchain/scripts/lstchain_r0_to_r0g.py
+++ b/lstchain/scripts/lstchain_r0_to_r0g.py
@@ -188,8 +188,8 @@ def main():
         log.info('FF-like events tagged as FF: %d', 
                  num_FF_like_with_FF_type)
     else:
-        log.warn('FF-like events tagged as FF: %d !!', 
-                 num_FF_like_with_FF_type)
+        log.warning('FF-like events tagged as FF: %d !!', 
+                    num_FF_like_with_FF_type)
 
     log.info('FF-like events not tagged as FF: %d', 
              num_FF_like_with_no_FF_type)
@@ -203,13 +203,15 @@ def main():
     # If a relevant fraction of FF-like events were not tagged as FF...:
     max_frac = 0.1
     if num_FF_like > 0:
-      if ((num_FF_like_with_no_FF_type / num_FF_like > max_frac) &
-          (use_flatfield_heuristic == False)):
-              log.warn('More than %d percent of FF-like events '
-                       'have wrong event_type!', int(100*max_frac))
-              log.warn('You should use heuristic identification of FF events!')
-      else:
-          log.info('R0 to R0G conversion finished successfully!')
+        frac_untagged_ff_like = num_FF_like_with_no_FF_type / num_FF_like
+        if frac_untagged_ff_like > max_frac:
+            log.warning('%d percent of FlatField(FF)-like events are not tagged as FF', 
+                     int(100*frac_untagged_ff_like))
+            log.warning('This may be due to anomalous events, like car flashes or LIDAR shots')
+            log.warning('More rarely, it could result from mis-tagging of FF events')
+            log.warning('A thorough inspection of the data check plots is recommended\n')
+
+    log.info('R0 to R0G conversion finished successfully!')
 
 def get_event_type(wf_hg, offset, evtype):