Banks aren't 'taking care of you' by blocking your account. They're taking care of themselves. If there is fraud on your account, they pay for it, not you. You'd be put out, but it sounds like you are being put out when there's no fraud, too.
I do agree, however, call your card provider and let them know you may have unusual charges. If nothing else, they may discuss your credit limits and help you make sure you have what you need available.
Agreed. They banks are only looking out for themselves. I have never paid a cent for any of the fraudulent charges that were made on my credit card.