Shirley's stock response in her new strategy to deal with disputed grades is pithy enough, but you're assuming the students and their parents give a lick about the other 170 students. "Do I deserve to be treated special? Hell yeah! That's why I'm asking."
A few things can help with this, both to benefit the student (and parents by proxy) and also to provide cover from administrative blowback.
1. Make the wee monsters sign off on a class protocol in the beginning, including an explicit statement about grading. Be clear that this protocol is a binding academic contract, and that both you and your students are bound by it.
2. At the logical intermediate points of the course, run the students through an academic audit/forecast ("here are your current scores, if this trend continues, the end-of-course letter grade will be something in this range ...). Make the wee monsters sign off on it. This ensures that there are no surprises, and it marks the students who didn't bother to get their audits as being unworthy of further consideration.
3. This may be asking for it, but maybe add some language to the class protocol about the correct policies about student accountability and privacy - including explicit language about the permissable scope of information available to parents. It might be worth the effort (or not) to actually draft a "Letter to Parent(s)", but this might just beg questions and cause problems.
Shirley might want to reconsider having any convos with parents, helicopter or otherwise. Unless your snowflakes are minors, parents don't have any right to know what grades the snowflakes are receiving or why, unless the snowflakes give consent. And I don't care if little snowflake shows up with written consent -- snowflakes who are legal adults have to handle their own shit, and that includes dealing with parents. My relationship as teacher begins and ends with snowflake. I don't even return calls or emails from parents.
OMFG, Shirley, WHY are you talking to parents? Here is the only thing you EVER need to say: "I'm sorry, but my students are adults. If you have questions about your Skippy's grades, please speak to Skippy. If Skippy has questions about his grade, he can come speak to me." THAT'S IT. If they push it, tell them how inappropriate their continued contact is. You've got to shut them out: when I've had students bring their mothers to my office, I offer only a brusque "Hi Skippy's Mom," and refuse eye contact from that point onward, speaking only to my actual student, the person who I'm paid to have to deal with. Parents get the point pretty quickly.
Just because there are college professors out there who think that FERPA is their ticket out of having to deal with a student's parents ("I'm sorry, Mr. Smith-Jones, but I'm forbidden by federal law from discussing anything about your son Johnnie's work in my class."), then the sad news for them is that FERPA does not necessarily impose such an informational blockade.
Looking at the relevant FAQ webpage from the U.S. Department of Education, if a student is claimed as a dependant on the parents' tax return, then regardless of the student's age, disclosure to the parent is not prohibited.
5. If I am a parent of a college student, do I have the right to see my child's education records, especially if I pay the bill?
As noted above, the rights under FERPA transfer from the parents to the student, once the student turns 18 years old or enters a postsecondary institution at any age. However, although the rights under FERPA have now transferred to the student, a school may disclose information from an "eligible student's" education records to the parents of the student, without the student's consent, if the student is a dependent for tax purposes. Neither the age of the student nor the parent's status as a custodial parent is relevant. If a student is claimed as a dependent by either parent for tax purposes, then either parent may have access under this provision. (34 CFR § 99.31(a)(8).)
I like Shirley from Shelbyville's suggestion a lot ("look, fucker, you're no exception," phrased in administration-approved language). I have two more to add:
(1) I'm forwarding all emails and voicemails from parents to my mom or dad, who will reply on my behalf. You're too busy playing World of Warcraft or fucking each other to send me an email, and I'm too busy making margaritas to reply, so let's just let our mommies & daddies handle it, okay? That's what we pay them for, anyway.
(2) Each male student whose parent contacts me about his grade should be required to disclose this fact to potential significant others. I suggest a stylish "Euro trash"-style emo tee that reads, "My mommy talks to my meanie teachers for me." Maybe even a personalized male thong for that special night when you meet the right girl?