Would this pi$$ you off?

What am I missing?  She bought pastries, offered to pay for her meals - which I gather you deferred.  

If I had been in her shoes, I would have paid for every third meal or so and sent you a very nice gift after the trip.

However, I'm guessing you don't know her financial situation or what your sister in law said to her before the trip. (Your sister in law might have said "Don't worry about the cost. They're rich. They'll pay for everything."

I think if you didn't want to pay for all this woman's meals (which is reasonable given that you didn't even invite her), then after the first meal you should have asked for separate checks. If you expected the sister in law and her friend to pay for gas, you should have made that clear before you started taking side trips.

I would have been very annoyed if I wasn’t asked in advance if the friend could stay at my home as well (I’m assuming you weren’t given a heads up on that?) That’s pretty rude of your SIL to show up on your doorstep with a friend in tow and expect you to accommodate her for an overnight weekend in your home.

Yes, easy to be wise after the event. I'm sorry she took advantage of you. Did SIL say/acknowledge that?

You say,Im sorry I am not comfortable with that, particularly during an out of control pandemic.

"Sounds like fun, but we will not be able to accommodate her at this time".  That's what you do.

Okay, that's weird, lol. 

Got it. You just have to out wait them.  Hahaha.  Sorry no advice.  It sounds like it was an uncomfortable weekend.  Sorry you had to go through that.

I would not have paid for SIL's meals either. When I go visit friends or family, I always pay my own way

I agree.

I've said, "Oh shoot! That sounds like fun, but I'm not set up to have anyone but you this time. Let's plan for something bigger later in the year" (or next year or never lol)

In this case, the pandemic is a perfect excuse, as there would be no way that anyone besides fully vaccinated family would be let into my house. And even then it is iffy.

Edited to add that I *did* have a situation where I hosted a small crop in November before the pandemic and one of my guests invited her mom and did not tell me. She just showed up with her in tow, as her mom wanted to "try" scrapbooking. I was pretty pissed, and unfortunately this person is now off my guest list. There wasn't really enough room to accommodate another person, and it made it very awkward. Sometimes it's "the more the merrier" and sometimes it's not. In this case, I didn't really know what to do. 

So I was re reading this and felt compelled to add that I was irked also because "trying scrapbooking" meant that she wanted to touch all our stuff, be taught the ins and outs of a cricut machine, manual diecut machine, etc...you would think her daughter would have talked to her about expectations before bringing her along, but no. Daughter is not a friend of mine, she was a co worker of one of the group, so she was already an extended include. Apparently I still have some feelings about this, lol. 

I think this is maybe the crux-what level of assertiveness are you comfortable with? I am pretty assertive and will speak up in almost any situation especially in one like this. But if you are not, or if you were worried about ticking off SIL or didn't want to cause drama, ect...maybe that impacts speaking up. I helped my friend with this, as she was uncomfortable saying "no" a lot, and we literally practiced her saying things like, "No, I am sorry that doesn't work for me." and other phrases like that. She was being a rug and especially trampled over by her MIL.

Just split checks. Or tell your SIL no. Or anything. I’m not a fan of making no effort in the moment to address things and then complaining about being the wronged party later.

I can let one meal slide - awkward situation, I suppose. But to let it repeat is on you.