We used the germophobe/illness reasoning to keep OSIL from bringing nephew to visit when she came for Wolverine's baptism.
Nephew (who was almost 3 at the time) is something of a spoiled brat, and SIL doesn't do anything to discipline him. We didn't want her to bring him (and destroy the house) when she came to visit, so we extended the Pedi's window of keeping Wolverine away from other kids by a few months.
"Oh, we hate to tell you, but the Dr.said that Wolverine isn't supposed to be around other kids until she's at least 6 months old because she's a preemie and her immunities could be compromised!"
Wolverine started daycare a week after OSIL left.