What should be done and reality:
Yes, when introducing new snakes into your colony it is best to quarantine for at least 30 to 60 days. Some say up to 6 months!
No matter the time you choose the reason for quarantine is to make sure the newly acquired animal is free from any contagious infections, viruses and so forth, that could be spread to their current colony. For boa owners they are most terrified of IBD. IMO the common threats to a collection are mites, ticks, IBD and RI. If during that time period there are no signs of illnesses or other things I mentioned then moving forward to introducing to the colony is done.
Reality, some people that have one or few snakes/reptiles don't normally quarantine at all. Their initial look over at the store is good enough for them.
So depending on how much you want to inform your customer is up to you. Ultimately, it is the buyers decision on what they are goin to do. As long as you did your job on the information part then your good.
* To better answer your question you should suggest but don't throw it down their throat as if they don't do it you will hunt them down. *
Good thing you did your research and reading keep it up.