People really shouldn't be saying that, because it simply is not true. MOST, wild caught clowns are older/more mature (even if they're smaller) than the captive bred clowns we see in our LFS. These wild clowns may be closer to settling down, establishing a territory, and making babies than many young captive bred clowns. Wild clowns may be more afraid, more stressed, than captive bred clowns. This may enhance the drive to seek the shelter, and security of an anemone. Wild caught clowns have spent the vast majority of their lives in a sea anemone. Many captive bred clowns, in our LFS, likely have never even seen an anemone.
While all of the above is indeed true, none of it erases, what has likely been, millions of years of evolution. I talk to people about this nearly every day. The only time I will give people my word, that their clown will go into their anemone, is if it's a natural symbiotic relationship. I haven't had to eat my words yet. It doesn't matter if the fish is wild caught, or captive bred. It will go into it's natural host. Period. Even when the natural host is not provided, all clowns, as they mature, will claim a territory. We have no way of knowing, for sure, where that territory will be, unless the natural host is provided. We have no evidence to suggest that where the clownfish was born has any effect on this decision.
Peace
EC