By now everyone has started thinking about Pesach, so maybe it’s time to focus on it here.
The Rambam paskens (Ch”uM perek 1) that someone who buys chameitz on Pesach gets malkos for bal yera’eh. Even though bal yera’ah is a lav she’ain bo ma’aseh, i.e. there is no action necessary to violate the lav; it can be violated by just passively failing to dispose of chameitz, nonetheless, if someone does take action, e.g. he/she goes to a store to buy chameitz, he/she would get malkos.
The Rambam paskens (Hil Gezeilah ch 1) that someone who pressures a neighbor into selling goods violates lo tachmod but does receive malkos because it is a lav she’ain bo ma’aseh, i.e. the desire which causes the violation of lo tachmod is a mental state, not a physical action.
Rav Scheinberg in his Mismeres Chaim (vol 1) asks: Why is it that even though bal yera’eh is a lav she'ain bo ma'aseh, there would be malkos if one takes action to violate the lav, yet even if one takes action to pressure or coerce someone to sell his property, there is no malkos for lo tachmod? What is the difference between these cases?
This is an easy one to answer if you read the post on lo tachmod a few weeks ago. Here’s the link if you missed it.