It can be a dangerous course of action which might be sound in theory but — ahem — perhaps a trifle risky in practice.

这可能是一次危险的行动，在理论上听着无缝可击，但—呃哼—真做起来却可能有点冒险。

It is not unknown for valuable display items to go, ahem, missing.

贵重的展品，呃哼，丢失的话，会众人皆知。