Explaining New Services Impact to Non-Tech Peers

Trying to explain to peers when they want to implement a new service how it affect us. Yeah, our process are lacking so bear with me. The conversation typical goes,
My Peer: The vendor said we can turn on x feature and let all these people register, login and do all sorts of cool stuff. Its all web based and doesn't require anything from your group. It even integrates with ldap and you have to do nothing. Plus everyone else is doing it.

Me: red flags. Vendor said...vendors will say anything for a sale. And everyone else is doing it? seriously? in a k-12 environment using that argument. wow. Just wow. Yellow flags: Logins = username and password issues, who are our customers going to call? Who is going to fix the logins? When do the customers login?
(There are good answers to these questions, but I'm not sharing). Next, Please god, tell me they use ssl and some decent security standards on passwords. LDAP. Ah, share my directory environment across the internet. yeah, thats a bit scary. (non-verbal, yes, i know i can limit access to ip, require a certain username and password {preferrably something that looks like the cat stepped on the keyboard}scope the ldap searches and a bunch of other things, but my group has to do this). Last, who and when do you want to this? I have to dedicate a resource to contact the vendor, contact the vendors tech people to ask questions (and yes those are 2 separate steps. We usually have to call the product AM. Then be polite to get the tech people so we can ask nuts and bolts questions).

The part that is hard to hiding your cards so to speak. Sometimes, it really is a good idea and product, but the questions need to be asked and answered. Trying to balance the questions so I don't look like I'm out and out saying no, but getting them to understand vendors, uh oh hell, lets be blunt, LIE, and it will have some impact on us anytime a new service turned on cause something will break and all technology items go through my help desk to start. Whether we "fix" the problem or route the call appropriately is something to discuss.