Can Grandpa's be trusted?

After work yesterday, Marie tells me that Lily was provoked into smiling twice while I was at work.

She's smiled before, but it's usually related to something in her world that we don't understand (or something we understand all too well). I asked if this smile was indeed the result of interaction, or just a random smile.

"I think it was. At least, it looked like it was."

"Were you able to duplicate the result?"

"No... but my dad said that he got her to smile."

"Oh really... and where were you at the time of this alleged smiling?"

"I was in the other room."

Now I'm sure Lily's grandpa really wanted to see her smile. But without corroborating witnesses, I ask you, can grandpa's really be trusted?

Especially since I've done everything in my power to make Binker smile, and all I get is a perplexed look that says, "Yeah, it's a tongue and you make noise when you stick it out. I get it."

The next time grandpa gets a smile, a word, or anything new, I expect photographic evidence or I'm not buying it!