Gossalyn, this is so helpful--thank you! Stupid question: would they be offended if they spotted me on a schooling show circuit next year with another trainer?
I think if you're honest w/ them, and make it about finances.. there's no way they could be offended by that. If it were my people I'd probably say something like "I love riding here, but it's really hard for me to afford.. I get that you are top notch and really good at what you do - but I need to downgrade and find a cheaper way. If I can get my basics down a bit, maybe in a year or so if I'm making a little more, I'd love to come back." The could always offer you a way to afford it. (then it becomes a question of is it money OR the social aspect?)
If you run into them or see them at a show - I would try and say hi and see how they are just to break any tension 'not talking' might cause. Light and casual. From a business perspective, they should want to keep good relationships with you too. It's easy to run the other way, but facing your fears and keeping communication open is probably better.
Even though to us clients, this is a socially awkward experience, from what I've seen barn people deal w/ these types of things all the time. Not just students - My current trainer used to work under another lady at the same facility we're at. My trainer plays it off like it's not weird at all (even though I'm sure it's a little weird!). I remember how awkward I was about quitting piano lessons (I went to another instructor) and the guy sensed I felt bad about it and basically said 'it's cool, people come and go, don't feel bad. If you ever need anything or want blah blah blah... always feel free to call)
Basically - I think it's generally more routine for these businesses to gain and loose clients. And it's generally in their best interest to say they are sorry to see you go & accept it graciously.. in case you ever need anything in the future.