Well the only way I could see it being abused (although admittedly I haven't thought that much about it) is someone deliberately makes a three digit prediction on a tricky match and then has a choice over which of those three numbers was actually a typo.

For example they could make a prediction of 326% on a a contestant they think will get a result somewhere in the low to mid 30's. They then selectively ditch either a 2 or a 6 depending on what would give them a better result. Should the contestant really underperform they could even ditch the 3 to get 26% although that would be harder to cover up mathematically. They would also have to deliberately make sure that none of the three numbers 32, 26 or 36 make the overall total equal 100 and then just put it down to them being bad at maths.

Farfetched yes, but certainly possible.