That lasts about 2 weeks, then they will understand that Donald means business.
No it will be hard for Trump to do much about it especially in states controlled by Democrats. Presidents just can't send in the military because they feel like it at best he can send in the FBI but there isn't really enough to make a show of force in an area. Unless of course it gets to full blown riot status. But even then the Governors are supposed to request help. There will need to be a huge outcry for the FEDGOV to step in and quell the situation if it arises.