It is important for people to know that, not all projects that steal money and disappear are scams and a lot of projects just offer huge bonuses to entice people into investing in their platform.
Offering too high bonuses is one of the major reasons why some ICOs fail.
Ideally i believe presale bonuses should not be more than 30% and the purpose of presale should be for a project to meet its soft cap, so presale allocations should be capped accordingly.
Offering too high bonuses either locked up or not will still cause some form of uncertainty for investors and prompt weak hands to dump.
Projects that offers 50, 70 or even 100% bonuses should be a no go area for investors.