Deeksha use your watermark all over your design no shame in that! Also if you think it's not working out for the host you can withdraw the submission later... Plus it will be obvious if someone copies other user's work and posts it they probably won't be awarded.
Do Not Seal. save your money...a serious artist can seal their own entry for a few bucks. Sealing will only encourage thieves...ooops....artist (as they call themselves) googling and copying other's work. :P
if you have any sense of observation then Bangladesh and Pakistanis top that category or whatever bs you're talking about. Only they are adamant enough to fool people by the use of stock content until they do.