MASSIVE boundary violation.
The neighbours don't know Alicia's family at all. They did this not knowing whether it would be appreciated, or whether Alicia's family had their own plans to decorate and just hadn't done it yet. It's something that's optional, and how it's done is a matter of taste, and they decided to impose their own ideas of what and how to do on Alicia's property WITHOUT ASKING.
This is not a sweet kind gesture, in my opinion. It might have been intended
as a sweet kind gesture, but because it was done without asking and without any knowledge of Alicia's family preferences, it crosses over into "I know what's right and I'm going to do it without consulting you". I'd be afraid they were going to turn out to be the sort of neighbours who walk straight in without knocking, chirping "It's only me! I knew you wouldn't mind, so I pruned your topiary for you!" "Er, I wanted to let it grow outů" "Oh, but it looks so much better this way! You don't need to thank me."
Shoveling snow is a bit different - it's got to be done (not optional, not really a matter of taste), it's hard work, it's a chore that's often seen as something neighbours do for each other. Even then, as previous comments pointed out, it's got the potential for things to go wrong; you find out your neighbour already paid someone to do it, or they just bought a new snowblower and have been waiting for the first snowfall of winter with eager anticipation, or you dumped the snow somewhere that's inconvenient for them. Which is why, unless it's an established thing that you shovel so-and-so's driveway every year and put the snow in x usual location, you ask
Maybe Alicia's neighbours had a regular thing going with the previous owners of the house, where they'd decorate for them, and everyone was happy. That was okay. Continuing now that there's someone new in the house and you don't know them and haven't said a word about it is NOT.
On the other hand, maybe Alicia's neighbours are controlling busybodies who have decided to make sure the street looks 'right' (according to them) and see nothing wrong with steamrolling over everyone else's preferences and choices to get what they want, and the previous owners moved to get away from them.
There's no real way to tell until she sees how they act in future. I've got to say, it's not a good sign IMO...