to be upset at other mums strange behaviour

[Babyramone]

I live near this other mother and our DS's both 4 get on well.
I have had a few problems with her in past (she tends to pick up and drop people as it suits) but get on quite well I thought.
On Monday she asked what we were doing for Halloween and I said that me and DS were going Guising (trick or treating)round a few pre arranged neighbours. She then invited us to join her streets group and then on to wee party afterwards. I accepted.
Yesterday she (noticed by others as well as me)went out her way to avoid me at nursery pick up and whilst walking down road with her other pal with me just behind and our boys all running together continued to blank me. When other mum got to her house she stopped to say goodbye and I over took them. When she caught up the 1st thing she said was that she was feeling tired and had decided not to go to halloween party and wouldn't be guising and that her ds was just going to other mums house for dooking etc. I accepted this and thought fair enough.
Anyway whilst out guising discovered she had been out with big group and the other mum and had been to every house she knew someone at except mine.
Today she said to me she'd had nice quite evening not out guising.
TBH not sure why it bothers me so much as she's done sim before. She's very good at arranging playdates and cancelling last minute feigning illness etc only to be spotted with other (obv more fun mum)
She once arranged for us to go to sotfplay together, called off as was ill. I went with DS myself only to see her there with fore mentioned other mum (they'd only just become friendly then). It was funny as she couldn't look me in face.
I really feel my ds as he likes her wee boy.
I've seen her do it to her DD's pals too.
Why would you be like this. I'd rather people were honest or at least she could've come to ours and said had changed mind.

I also accept if she doesn't want to be pals or spend time with me and ds any more but why keep inviting us too?

Should I just ignore this. What would you do.
Is all so petty.
Bloody mum politics.

[hifi]

ignore her, others will twig soon enough. new to all this mums politics stuff and refuse to play. at nursery they say hi one day and not the next, ignore you at the park. my motto is now one strike youre out. its like being back at infants.