I typically use the 2-lead metal can style crystals, but for our frequency stability needs our crystal manufacturer recommended we use the 4-lead flat SMD style crystals (sample picture attached).
I was looking through our reference design, for this product and the symbols for the 2 lead can style crystals are mostly used for the MCU.
In one separate reference design they use a 4-lead SMD symbol for the same MCU. The layout guy only connected one of the GNDs pads in this design.
Is there any conceivable reason NOT to connect both GND pads on this 4-lead crystal? Is there something I am not aware with these 4-lead crystals?
Should I use a separate via for each GND connection?
I've seen layout guys not connect all the GND pads on a mechanical switch, for seemingly just putting less traces on a board.