YANBU OP
I used to live in Madrid and we would often get friends and family letting us know they were coming to visit without checking the dates with is first, and yes while they booked their own flights/hotels they were 100% booking with the expectation that we would spend time with them and it's the presumption that you can drop everything to accommodate their visit that is unreasonable.
95% of them understood that if they said "We are flying into Madrid for a week on XYZ dates!" with no prior warning/discussion of a visit then they would run the risk of us not being available for the whole time and we were happy to suggest things for them to do but couldn't always join them/guide them because we had our own commitments but there was about 5% who were scandalised that we didn't drop everything to host them the entire time.
I remember one pair of (now ex) friends who announced on a Monday that they were flying in that weekend and were expecting us to pick them up from the airport at 3pm Friday afternoon and then spend the whole weekend with them and drop them off at the airport on Monday lunchtime.
What they had failed to take in to account was that:
a) ExDH and I were both teachers who worked M-F 9-5 in our schools so couldn't take Friday afternoon and Monday morning off. We worked in the city centre and could possibly have managed to pick them up if they arrived at about 12/1pm as we had 1-3pm as our lunchtime so by the time they arrived, got luggage etc we could have hopped a taxi to the airport, picked them up and had a quick catch up in the 30ish minutes in the taxi from the airport back into the city centre to plan their weekend, drop them at their hotel, grabbed a sandwich for lunch and been back at work on time ... but it would have cost us about €80 in taxis
b) DD had booked activities Friday evening and Saturday morning which we weren't going to just cancel at short notice. If we'd had more notice we could have arranged a babysitter to pick DD up from her class on Friday and/or Saturday so we could have spent more time with them (loads of our neighbours had Au Pairs who were happy to do a bit of babysitting on Friday evening/weekends for a bit of extra spending money)
c) it was a friend's child's first holy communion on that Sunday which we had been invited to (FHC is a massive deal in Spain and was a whole day thing of the church service then going out of the city centre to a fancy place for dinner/drinks for the rest of the day) so we were not going to be available at all on the Sunday
When we informed them "Sorry the only times that we are available that weekend are the Friday evening and Saturday afternoon due to other commitments. Tell us if there's anything in particular you want to do, we'll let you know what's going on this weekend so you can make the most of your time. We'll make a reservation at one of our favourite restaurants for Friday night and then we can do something fun on Saturday afternoon" they were furious we weren't dropping everything to be at their beck and call ... Strangely after that weekend we didn't hear from them again.