Even at 8 years old (when many Boxers are dead or close to it), I don't think our Boxer Jake would act that way. It's not that he'd be aggressive towards a baby, but he'd probably try to play with one a bit too rough. lol
My Boxer Diego is like that...when he is being lazy...but seriously, there is no way I'd leave a baby on the floor with him when he is in PLAY mode! That is very cute, tho and shows how sweet Boxers are!
You can see the look of concern on the baby when the boxer puts it's paw over the baby's hand...the baby was like..."uh oh", then the dog yawns and the baby smiles...that's really cute. That's a big boxer.
While I wouldnt leave my baby unattended to find out I do know ours loves kids. I have some neices and nephews who are 2 and under. If they are sitting on the floor Bella will go sit by them and give them a good face wash.