Final answer:
Costumes were not mentioned as being allowed at Savanna's party, and the context notably involves a legal ruling where a strip search at school was found to be excessively invasive and a violation of Savanna's Fourth Amendment rights.
Step-by-step explanation:
No, costumes were not allowed at Savanna's party. The context provided alludes to a legal case concerning Savanna and her rights under the Fourth Amendment. A strip search was performed on Savanna at school, which the Supreme Court later determined to be excessively invasive and a violation of her rights. Savanna's party, where the costumes served a specific purpose, is separate from the legal issue regarding the search at school, and there is no mention of costumes being permitted at the party in the information provided.
Given the legal nature of the incident, it's essential to note that the Supreme Court recognized the strip search at school as an embarrassing, frightening, and humiliating experience, which failed to adhere to the constitutional protections afforded to Savanna. A search of her belongings could have been considered reasonable, but extending the search to require her to remove clothing and expose herself was deemed unwarranted.