Party planners are never under any Hashgocha
Party-Planners- Can a hashgocha control them? We doubt it.
They bring anything & everything from literally anyplace.
Pop corn machines- others may use butter & then used for fleishig party.
Chocolate machine- was used with dairy chocolate then used for fleishig affair.
Hot-dog machine- used for any brand hot dogs previously.
Candies, cakes, etc from anyplace.
Dishes, utensils from anyplace.
Reb Dovid Feinstein, Shlita said "A party planner on a shabbos event without chilul shabbos?, I don't think it can happen".
All Party-Planners must be under a strong Hashgocha, or don't use them.