Bot are very common in telegram bounty and twitter also duplicate and fake accounts are very hard to determine you can check the entry form one by one to filter duplicates even if you hire bounty manager this is not assurance that bots will be eliminated.
you are right, bot is not going do anything meaningful, see i like those Managers that run their campaign with manual, and the problem is that in bounty so manager do not have the time to scrutinized their participants before selecting.
I also suggest to limit the bounty participants to avoid spamming, less participants who can do the job effectively is better than hiring many.
Even though they have least of participants they will still spam, some people usually adventure into spamming unknowingly due to its way their establish theyself in the forum from the day one (1) they join community.