myelinsheath

Would anyone here happen to know / have an opinion on what the protocol is for someone waitlisted at their first choice PhD program and holding on to another offer? The deadline for me to accept an offer at hand is April 15, but my waitlisted program has told me that I may not hear back until a few days after the 15th, since that's also the deadline for their admitted students to make a decision. Assuming I don't hear back from them by the 15th, should I accept the other offer? Or would it be okay to explain my circumstance to the program I'm admitted to and request for an extension? It feels a bit unprofessional to accept an offer and then withdraw later, especially for PhD programs which have smaller cohorts. But I obviously also don't want to end up in a situation where I have no place to go. I'm waitlisted at MIT MEMP, by the way.