Many services will auto-translate :) into something else, like a colourful unicode icon. If you prefer to keep your smiley looking like just a smiley, (: is an effective workaround.
There's also an upside-down emoji smiley with its own distinct mood. Hopefully services don't start translating (: into that, they're used quite differently!
Thank you so much for the heads up. I'm only doing this because it's fun! I love using Linux and I feel like I learned a ton from this.