Butterfly Watching vs ID's

Last week in Florida I entered the following sightings in a Nature Centre's "Sightings" book: Gulf Fritillary, Zebra Longwing, Little Yellow, Cloudless Sulphur, Gray Hairstreak, and Cassius Blue. Half of these were incorrect and one other species was not recorded. Fortunately I got photos, and looking at them today I see that: my Little Yellow appears to be either a Barred or a Dina (will post image later), my Cloudless was a Large Orange, my Gray Hairstreaks were Mallow Scrub Hairstreaks and Martial Scrub Hairstreaks. This incident raises the question of how reliable are id's made purely on sightings? Guess it depends on who is doing the sightings and how familiar he/she is with the local fauna. The unfortunate aspect here is that my recorded "sightings" seem plausible and may be accepted as factual. Thankfully, none of this applies to contributors of BugGuide as we actually collect the specimens via photography.