The worst could happen, but use grunt. Always.
A little lesson from wasted time.
Code could be wrong, thus it has to be tested, and tested, and tested. Automate that test. Do not wait to waste any more time.
A note on grunt is that shell can do the most, for example lftp is very good:
command: 'lftp -e \'put ./myfile.tar.bz2\' ftp.mytargetsite.com'
Is better than use grunt-ftp, or grunt-ftp-deploy, or whatever.