Stakeholders who do not support the trial should be involved too because not involving them is inciting more resistance from them. Remember stakeholders are people of influence in communities at different levels.
Involving them enables you address their concerns or minimize their negative reactions that would impact on study acceptance.
The ideal is to know how to involve them and when to involve them. As long as they are involved in early stages, their opposition is likely to reduce. People with influence usually expect you to recognise them and their importance. That could save alot of resistance, misconceptions and other undesirable outcomes for the trial.
