I would be surprised if any HT saw 'expense' as a valid reason either DeWe.
When DS1 was tiny and we couldn't afford a holiday, DH took a week off work and we did a few day trips but still had that lovely family time together. DS1 wasn't at school but it was the summer holidays. We couldn't have afforded a proper holiday in or out of term time at the time.
Often people will say that family time is very important but IMO that does not have to be spent on a fancy resort in the Caribbean.
We can afford holidays now and end up spending a ridiculous amount more going in the school holidays but there may be a time when we need to take a week out in term time so I would genuinely want it to be a valid reason.
When I was younger hardly anyone went abroad, most people camped/caravanned, mainly in the UK but some people who were better off went to France. We were teenagers before we went on a plane and it was always school holidays, no one I knew took term time holidays. I think we are as a whole more 'entitled' now and seem to have an issue with anyone telling us what we should or shouldn't do.
If I want to take my DCs out of school I will but I will not moan about a fine or unauthorised absense, this is nothing new IMO.