Of course a disincentive to sell will be created by your proposal! Any lien that comes close to offsetting or canceling out the owner's gain will do that. The lien doesn't have to exceed the gain to create a disincentive. Why would anyone sell for little to no gain? Any time the potential gain is decreased, a disincentive to sell is created.

Furthermore, not only does this create a disincentive to sell, it also creates a disincentive to buy. Buying property becomes a lot less attractive when the same disincentive that applies to the current seller will apply to buyer in the future, when the buyer decides to sell the home.