Some years I've gone, some I haven't. I don't even know when it is this year. Suppose I'll find out the week of, when well-meaning, but clueless JW family invite me.
As much as I'm forever out of their control, I really don't have a problem with going to the memorial, if it makes elderly parents happy. It's one hour a year. Big deal. No different than a name only Catholic showing up for xmas mass once a year. I don't like going to cheap cafeteria style restaurants either, but the old folks like it, so that's where I take em to eat. Their time is limited. Let em enjoy it, even if it isn't my thing.
Some comments mention that 'once-a-year' attendees are looked down on by the rest of the JWs. That doesn't bother me a bit. I'm already looked down on. My being there or not being there isn't going to change that. If I decide to go, I wear my independence from their control on my sleeve. No tie, no suit jacket, beard in place. Be confident, don't shirk from talking to anyone, let em know that being away from religious fanaticism has done you well.