I'm not looking to make money off it. If they have a problem, they could remove it.
I hope you're aware that three copyright takedowns will terminate your channel; so I wouldn't act so complacent about the possibility.
Once a channel is terminated, its owner is banned from YouTube for life; and prohibited from owning, accessing or creating any further channels. If the banned owner has multiple channels or accounts, each will be found and terminated eventually.
You'd therefore be much better off licensing your backing tracks.