Again, if they lie to you, you’re covered. It’s about your intent. Do you intend to offer goods and services in GDPR-affected countries? If you have a checkbox like this, then you clearly don’t, and GDPR does not apply to you.
I think that much greater threat is comming from a direction of US companies you use than from EU courts this (again, might) become another "patent trolling"-like action from some US companies.