I noticed a few libraries, in their micro subtype b footprint designs, include round mounting holes very near (touching) the pads. In Eagle, these end up giving me dimension errors. I tried researching this on the web, but I could not find anything specific about this.
Can I safely ignore these errors? Should I edit the part and remove the holes? What is the reasoning behind adding those?
I've seen a couple of USB connectors with plastic alignment pins in a similar place. However they are usually slightly further from the pads. If your connector has alignment pins and you don't place the holes, the connector won't fit.
My suggestion is the same as for any component - don't trust that the footprint you have found is correct/accurate - most won't be.
Always verify the footprint against the manufacturers datasheet for the connector you are using. Make any changes as required.
