Came here because I was starting to think I was the SIL 🙈 until I remembered I'm too averse to saying anything to my family about the incessant egg and gift buying in case it causes them to speak badly of me (and it wasn't Thorntons eggs!)
I can see where your SIL is coming from OP, in the nicest possible way. My kids ended up with a LOT of chocolate this Easter without DH or I even buying them any, between both sets of grandparents and my DGM. My SIL without warning started buying them eggs last year, which left me stuck as by the time the eggs arrived at ours Easter was long gone and I hadn't got anything for hers. Had to buy something else to send. Same again this year, but I was made aware by my DM shortly before Easter so was able to get something arranged.
Personally I don't like buying for buying's sake, and that goes for Christmas too. DH is the same, and fortunately his family are too. I enjoy giving thoughtful gifts, and made an agreement with my DB and SIL a few years ago to only buy the kids Christmas presents but even with that, they deviate from the requested presents and give extra whereas I don't and then worry that I'm being perceived as tight (despite buying exactly what was asked for).
I don't know how to broach the egg subject though without coming across as rude, especially as my DB wasn't overly impressed with the 'kids only' Christmas gifts a few years back when I had one child and he had none, and now I have 2 and he has 1. He's made comments about me doing better out of that arrangement than him (he means in terms of the spending on the gifts)...so if I were to try to stop the eggs now, I know he'll perceive it as being worse off as 'he' wasn't on the receiving end of as many eggs during the period as 'I' was.
Christ that sounds mental when I write it down 😂
Families...