Saying no to miscellaneous administrative tasks as a Grad student In my university, graduate students under scholarship have to perform certain tasks like tutoring and grading. I have no problem with that since it is part of the contract.

There are also some miscellaneous tasks like offering to help out for a departmental party (takes 10 hours over a few days), or volunteer to bring some visitors around the school, etc. These are theoretically on a voluntary basis, but when no one volunteers the admin staff starts to get very pushy and "hard sell" people to volunteer. To get a sense of how pushy the admin can get, I recently had to reject the same task thrice (via email), with the admin getting increasingly curt and rude in their email. (The administrators are not professors, they are in charge of departmental duties including paying our stipend.)

I plan to reject around 90% (edit: maybe 50-60% selectively, as there are some events that I am genuinely glad to help out) of such "voluntary tasks", and have already rejected a few, and accepted one. (I am a new graduate student) Will there be any negative repercussions if I do that (reject majority of the tasks)?

Most of the tasks require at most 10-20% of the students to help out (around 10 helpers out of 60 students). Some tasks just need a single or one or two volunteers. 

(Edit: my personal background is that I used to be a "yes" person to the extent of burning out (previous experience not in school), hence I need to learn how to say no firmly to certain things. I have also discovered through the hard way that "yes" people get asked to volunteer more and more, few  actually takes into account that I am already volunteering for another event and may need a rest. )

Also are there any tips on how to say no, with respect to Academia? I may try a new strategy of ignoring such emails, the emails do "require" us to respond whether we can make it or not, not sure if ignoring such emails may be a better policy since I think that is what some students do.

Edit: I have found a personal solution is to read up on more self help books on assertiveness. Thanks for all the help (including sarcastic comments, which confirms my new belief that I should not care about what others think). Especially thanks to Professor Romik for restoring my faith in humanity. Hope this thread can help students facing similar predicaments.
Will there be any negative repercussions if I do that (reject majority of the tasks)?


Of course there is no way to say for sure whether there will be any negative repercussions if you keep rejecting those requests. However, frankly, it seems likely to me that:


You will come across as kind of an ass to the administrative staff, and that's not great at all. If your university is at all like mine, there will be a number of times when you need their support in, well, administrative matters, and you will be very low on their priorities list if you make it a point to never or rarely help them out.
You will come across as kind of an ass to the other students, who will surely notice that you never help out and they need to take on more of those duties as a consequence. You will invariably need their help at some point during your studies, and it's not unlikely that they will not be thrilled to help you out then either.
You may come across as kind of an ass to the faculty, which tends to notice if certain students are never volunteering for anything. The extent to which they care is another question, but it seems unlikely that they will consider this a positive attitude. In the worst case, somebody may remember this when the time for letters of recommendation comes up after graduation.



  Also are there any tips on how to say no, with respect to Academia? I may try a new strategy of ignoring such emails, the emails do "require" us to respond whether we can make it or not, not sure if ignoring such emails may be a better policy since I think that is what some students do.


If you really think you should keep on saying "no" to those things, it seems fair to tell the administrators directly that you are not available for volunteer work. They will likely be annoyed, but they will also be annoyed if you keep turning them down. I don't think there is a way to turn them down without annoying them in any way.

(and please don't start stringing together increasingly less plausible excuses - that's just childish)