There are three very good reasons committed the ears.
1. Cost, making the ears on the magazine catch requires 20% MORE material and a third setup in a CNC machine. A very complicated setup I might add. Also three additional tools that have to change and make the cuts. This adds to the COST a lot. This is why V3 Tactical sells theirs for $30 ea, and I can make them for 11.99.
2. Flexibility. Boyds stock very a lot, and about 5-10% of my customers have needed theirs modified to get the magazine to fit. It is not a problem with my QC of course. The HAAS CNC I use has a tolerance of .0002 over an inch that keeps my Magazine Catche tolerances supper tight. Its the Boyds stocks that vary so much. Omitting the ears made it a lot easier to fit these to a variety of inconsistent stocks.
3. Smooth functioning, I noticed from the get go that omitting the ears just made putting in the mag and removing it faster and smoother. Sometimes the snap on the mag gets hung up on the ears of Boyds plastic catch so for this reason I omitted them.