Thanks for the update.
Yes, people do all kinds of weird things to avoid payment–I could tell you a list of what I’ve seen clients do, various “innocent” types of bad checks, reporting cards stolen immediately after giving the number, etc. but that’s for another thread. Take home point: giving false/incomplete payment info is a huge red flag.
If I were in your shoes, I would collect the check for Feb board, confirm with your bank that it is good (this can take an annoying period of time) and then give notice. If there is a delay in board payment, I would give notice as soon as it is late. It’s better to get a horse moved quickly when there is a payment issue, versus the horse continuing to run up bills at your place that might also go unpaid.
You don’t need “cause” to give a boarder notice, you can give a boarder notice for any reason. It’s extremely reasonable to let a boarder go due to drama/concerns regarding payment. Typically there’s an obvious issue which can be politely referenced as, “I’m sorry, I just don’t feel like this has been a good fit,” and I think this is one of those situations.
Notice periods are usually written into boarding contracts so that both BMs and clients can plan for normal transitions, but they don’t give a non-paying client the right to stay out an unpaid 30 days. If you aren’t getting paid, you have every right to ask a horse to be moved immediately (with the expectation that it might take longer than that for it to actually happen).