Setting them up for success

So I sent the toddler away today. To Nana's and Papa's for two days and two nights. She is gone and ouch, my heart hurts. She drives me bonkers but she is my heart. And my heart is gone. For two days and two nights. Sniff, sniff.
After Emmy left the house was really quiet. I put Parker to sleep and then just sat and kinda stared out the window for a while. Parker woke up about an hour later and you could just tell that she knew Emmy was gone.
Here's the thing. As far as children are concerned, Parker is an EASY baby. Please don't hate me but my child has been sleeping through the night since she was about a month old. And even early on she only woke up about once a night. She doesn't cry a whole lot unless her sister smacks her in the head or rolls over on her while she's quietly lying on the bed. She's extremely smiley and giggly and just plain happy. But she got up from her nap and knew her sister was gone. We played on the floor and I could actually devote all of my attention to her. I was all her's for the rest of the afternoon. What does she do? Rolls over! Yep that's right; she rolled over and over and over and over. It was like she was performing for me. She was all grunting and huffing and hauling her chubby little baby legs from side to side until she rolled over. And Mommy did nothing but clap and smile and coo at her. This went on for twenty minutes. I was completely focused on her for 20 minutes. No "Hold on Parker, Emmy has to go potty" or "I'll be right back, Emmy wants juice" or "I've got to go help your big sister." I was all hers. No competition.
And so began the crying!
She would roll half way over and get stuck, cry!
She dropped her toy, cry!
She couldn't see my face, cry!
And when she cried, I was right there with all my love and hugs, no waiting.
So my question is, Has she been neglected all this time or is just now figuring out what every girl on the planet knows... Crying is a very effective form of manipulation that one should master as early as possible.